Mario Tennis Aces

Mario Tennis Aces is a multiplayer sports game for the Nintendo Switch and the eighth installment in the Mario Tennis series. It is also the first game in the series since Mario Tennis: Power Tour on the Game Boy Advance to feature a story mode, in which Mario must advance through a number of missions and stop a powerful tennis racket, Lucien, from destroying the Kingdom of Bask, the game's setting. While the gameplay engine appears to be based on that of Mario Tennis: Ultra Smash, it introduces new techniques to the traditional tennis gameplay of the series. One of the prime features in this game is an energy gauge which can be charged throughout the course of a match by rallying the ball. Energy grants the ability to slow down the time during a match in order to catch a ball more easily. Under certain conditions, it can also be used to stop time and launch the ball from a first-person perspective to the other side of the court through Zone Shots and Special Shots. These are powerful types of shots that can damage or break the opponent's racket if not countered correctly.

The game also offers expanded online features, mostly through tournaments and co-op challenges, where players can participate to unlock exclusive content. Since release, the game has been updated with new playable characters, story mode levels, modes of play, and tournament features, most notably a rank classification.

Basic gameplay
As in a game of tennis, players have to hit the ball back and forth until one side misses it. In normal matches, players who earn a successful shot score 15 points; at 40 points, players earn a game point, and have to score another successful shot in order to win the game. A deuce commences if both sides are tied at 40 points, where they need to score a two-point advantage to win the game. There are two games in one set, with the number of sets depending on the rules of the match. A tiebreaker is used to settle the match if the players are constantly tied throughout the match. In tiebreakers, players score one point for each successful shot. Seven points are required to win the tiebreaker and, by extension, the match. If players obtain a 6-point tie, they need a two-point lead in order to win.

Matches can be played in singles, involving only two players, or doubles, involving two pairs of players. In every match, there is a server and a receiver, who switch sides at the start of every game. The server has to launch the ball on the opposite side of the court, otherwise it will be a fault. Two consecutive faults (double fault) will cause the opponent to score. The speed of the ball is briefly displayed at the top of the screen when it gets served. The ball has to stay within the boundaries of the field; if it lands out of it, the opponent will score. Landing the ball on the court's sidelines has the same effect in singles matches, but this is allowed in doubles.

Special features
Characters have an energy gauge that can be used to perform Zone Shots, Zone Speed, or Special Shots. The energy gauge can be increased by simple rallies, by charging shots, or by performing Trick Shots, which require proper timing to hit the ball back. Zone Shots can be performed upon reaching a rotating star point on the ground, and allow the player to aim their shot anywhere on the court using motion controls. The longer they take to aim, the more energy it depletes. When energy is fully depleted while in a Zone Shot, the stroke loses form, resulting the ball flying high in the air. Zone Speed allows the player to slow down time to allow them to reach a far-off shot in time. Special Shots can be performed from anywhere on the court and require a full energy gauge. Zone Shots and Special Shots are able to damage rackets. Rackets can withstand three Zone Shots or one Special Shot before breaking, and after being broken they are replaced with a new one, forcing the player to retire when they no longer have any usable racket. With proper stroke timing, these shots can be blocked, increasing the character's energy gauge and protecting their racket from damage.

In doubles, each pair shares one energy gauge, and if a player's racket breaks during a rally, that player's team immediately loses the point. Also in doubles, each player has their own racket counter. When playing in doubles, the match will end if just one player loses all of their rackets (no matter how many rackets that player's teammate has remaining) and that player's team immediately loses. Exclusive to doubles, the result screen also shows X marks in the sections where a player's racket took damage, and the X marks are colored as appropriate to show which opponent did the damage to that player's racket.

Other than the base style of gameplay, the game also includes a "simple rules" mode which excludes the new types of shots.

Types of shots
Shots can be charged to increase their power by pressing their corresponding button early before the player hits the ball. Max Charges result in powerful, quick shots that can push the opponent back. These can be countered with certain shots to reduce the push. In matches with standard rules, charging up a shot confers the player energy which can be used to perform Zone Shots and Special Shots. However, simple rules only allow basic tennis shots. {|class="wikitable center" !colspan=3|

Basic shots
!colspan=2|Shot !Description !Topspin ! !Slice ! !Flat ! !Lob ! !Drop Shot ! !Star Shot ! !Leap Shot ! !colspan=3|
 * align=left|Topspins are shots that cause the ball to spin forward and bounce high. The shot is denoted by the red trail behind the ball. A Max Charge topspin can be countered with a slice.
 * align=left|Slices are shots that cause the ball to spin backward and bounce low. The shot is denoted by the blue trail behind the ball. A Max Charge slice can be countered with a topspin.
 * align=left|Flats are shots that do not inflict any rotation on the ball, making it move on a straight trajectory. It is faster than topspins and slices. The shot is denoted by the purple trail behind the ball. A Max Charge flat can be countered with another flat.
 * align=left|Lobs are high shots that send the ball far into the court. The shot is denoted by the orange trail behind the ball.
 * align=left|Drop shots are low shots that send the ball close to the net with little bounce. The shot is denoted by the white trail behind the ball.
 * align=left|Star shots are shots that return the ball at high speed. These shots can be performed when the player stands on a Star Point, which usually appears on the ground when the ball gets sent high into the air by the opponent or when the player's energy gauge is filled one third. They are slightly more powerful than Max Charge shots, pushing the opponent behind when countered.
 * align=left|Leap shots are weak shots that are performed when the character leaps for the ball and loses form. When the character lunges to hit the ball, it gets sent back at a low speed, and the character gains no energy. If the ball is sent high into the air, the opponent can strike it back with a star shot. Leap shots can cause the ball to land out of bounds or on the same side of the court.

Exclusive shots
!colspan=2|Shot !Description !Trick Shot ! !Zone Shot ! !Special Shot !
 * align=left|Trick Shots are shots that involve the player moving quickly towards a distant ball to hit it, usually slowing time in the process as in a Zone Speed. Players spend energy to perform Trick Shots, but if their timing is right, they can gain energy instead.
 * align=left|Zone Shots are shots that can be performed on a rotating Star Point once the player's energy gauge turns yellow. They can also be performed when the player is serving. As of version 3.0.0, the Star Point also turns turquoise when the character stands within it. The ball can be aimed anywhere on the court in a first-person perspective, then struck with power. The opponent can successfully block a Zone Shot with proper timing. However, if the ball is hit too early or too late, the racket will be damaged.
 * align=left|Special Shots are the most powerful types of shots in the game. They can be performed from anywhere on the court, but only when the player's energy gauge becomes full. They will trigger a short animation which shows how the character is going to perform the shot, after which the player can aim and shoot the ball in a first-person perspective like Zone Shots. Unless countered with a block, Special Shots have the power to break the opponent's racket instantly.
 * }

Adventure
Adventure Mode acts as the game's story mode, featuring cutscenes and levels like a typical Mario game. It is revealed that the game takes place in the Kingdom of Bask, which was destroyed in ancient times by a powerful tennis racket named Lucien. After being discovered and stolen from the Bask Ruins by Wario and Waluigi, Lucien is rewakened and proceeds to possess them and Luigi during a match on Marina Stadium. Lucien's motivation is to seek five Power Stones scattered throughout the kingdom, which conceal his true power. Under the guidance of Aster, a mysterious voice, Mario sets forth to retrieve the five Power Stones before Lucien and defeat him once and for all. On his journey, he must complete various missions and level up to become stronger.

Toad accompanies Mario throughout the jorney, acting as his spokesperson, as Mario does not talk. After selecting a mission on the map, a short dialogue between Toad and other involved parties will commence, then the player can begin the mission. Mario can exit to the world map or (as of version 1.2.0) retry the mission if the player pauses or fails it.

For more information about this mode's contents, see below.

Tournament
Tournaments are successions of matches (here also called rounds) in which the player can challenge computer opponents or online worldwide opponents in an 8-player bracket. They return from previous Mario Tennis games after being absent in Mario Tennis: Ultra Smash. Tournament matches feature up to three sets, each divided into two games. If players are tied by the end of these sets, there will be a tiebreaker that decides the winner of the match.

COM Tournament
In computer tournaments, the player can choose to compete for the Mushroom, Flower, and Star Cups, each representing a different difficulty level. Computer tournaments consist of one preliminary round, semifinals, and finals. Each cup has a number of possible opponents that are selected from the game's base roster; in other words, they cannot be characters added after the game's release or characters in alternate costumes. The character used for winning one of these cups receives a small crown next to their name and under their icon on the character selection screen of that cup.

The table below lists all cups with the corresponding rules and opponents.

Online Tournament
Players can connect to the internet to compete against other human players in online tournaments. In order to participate, players need to have the latest version of the game and a Nintendo Switch Online subscription. They can participate in the standard class, simple class, or (as of December 2018) the doubles class. For the doubles class, the player can pick a partner either locally or online.

As of December 2018, online tournaments consist of one preliminary round followed by a semifinal and a final round, similarly to how the COM tournaments are structured. Originally, tournaments featured three preliminary rounds instead of only one. In every online tournament match, there is one set with two games and (in the standard and doubles classes) each player has only two rackets.

Players can obtain rating points by winning matches, or lose points otherwise. The amount of points earned or lost in a match depends on the player's performance. Rating points determine a rank from D- to A+, which are used to match players of similar proficiency. If someone has rank B (2,500 points) or higher, they will start each tournament from the semifinals. When players enter a month's tournament for the first time, the points they had obtained during their last online tournament period played are rounded and kept for the current tournament period, along with their rank. Each tournament period keeps track of player statistics such as tournament wins, round wins, and round losses, with the latter two being calculated in a win ratio.

When the player wins a championship, they are congratulated with a trophy resembling the Special Cup from other Mario titles. However, unlike in COM tournaments, characters that are used to win an online tournament are not given a crown on the character selection screen.

Between July 2018 and July 2019, playing at least one match in an online tournament each month awarded the player with an additional character as a participation bonus. Starting with the January 2019 tournament, the player can also earn Participation Points, which can reward alternate costumes.

If a player disconnects or is disconnected during a match, the match will be forfeited and the opponent will win. Players who forfeit the match in this way too many times will not be permitted to participate in the rankings.

Co-op Challenge
Co-op Challenges were added as part of the version 2.0.0 update. In this mode, four players (which can be local and online) participate in a limited-time online event to earn points that can unlock alternate costumes and colors for playable characters.

The player can wait 60 seconds for the console to search and connect to other players. If not enough players are found in this timeframe, the game will substitute them with computer players. The player can choose to keep searching for online players for 180 more seconds.

For more information about this mode's contents, see below.

Free Play
This mode allows players to play custom matches at their leisure. Up to four players can join in Free Play, both locally and online. By pressing the or  button, players access a menu where they can change the match rules, with the following options:

Swing Mode
In this mode, players can use motion controls to play tennis. This mode is played solely with the left or right JoyCon, which may be chosen depending on the player's dominant hand. During matches, the camera is positioned lower than usual. There are multiple features in Swing Mode, all of which only allow simple tennis rules (i.e. no Zone Shots, Special Shots or Zone Speed).

Regular Ball
Matches can be played with a regular ball, just like in Free Play. Most rule options from Free Play are also present here, though the player cannot adjust the Play Style and, by extension, the KO Loss. One added option is to activate the, wherein the player is allowed to challenge the decision that the ball was shot out of the court. Up to four local players can join a match in Swing Mode.

While rallying a ball, players can hit it a bit early to send it towards the corner on the opposite side from their racket (pull shot) or a bit late to send it towards the corner on the same side as their racket (push shot). If the ball is hit too early or too late, it will be sent at a low speed (similarly to leap shots), allowing the opponent to strike it with a flat shot and return it faster than usual.

If players have enabled the challenge system, they will be allowed to challenge whether the ball bounced very close to the court's bounds and was called out by the judge. During a challenge, the camera zooms into the spot where the ball bounced, showing precisely if it landed in or out of the court. If the ball has merely touched the boundary line, it is considered to be in the court. If the challenge is successful, the call will be overturned and the opponent will receive no points, but if it is not, the opponent will receive their points and the player will lose one challenge. The player can incorrectly challenge a call three times, after which they can no longer challenge a call during a match.

Big Ball
Matches can also be played with a large-sized ball, which is slower and easier to hit than a regular ball. All basic rules and features seen in regular ball matches apply here.

Special Game
In this feature, players can play the Boo Hunt and Shy Guy Train Tussle minigames both cooperatively and competitively. Players can earn different high scores for each mode of play, and in cooperative mode, they also receive a rank based on their high score. By pressing the or  button while highlighting a minigame, players can view the rules of that minigame.

Rally Challenge
Similarly to Mega Ball Rally from Mario Tennis: Ultra Smash, players have to rally a ball as long as possible. The game can be played with up to four players.

The ball starts out large-sized and moves slowly. With every 10 rallies, the ball's size decreases while its speed increases, changing colors to reflect this. If the ball lands on the sidelines of the court, it is not considered out, even if the game is played in singles. The game is over once one of the players/teams misses the ball. No high scores are recorded for this feature.

Change Number of Players
This feature enables secondary players to join or leave the game by synchronizing different JoyCons with the game.

Settings
In the Settings, the player can adjust miscellaneous functions in the game. These include: Player controls can also be changed in the character selection screen by pressing (Dual Joy-Con/Pro Controller) or  (Joy-Con sideways), as well as the character's dominant hand by pressing  (Dual Joy-Con/Pro Controller) or  (Joy-Con sideways, Joy-Con vertical in Swing Mode).
 * enabling or disabling music during matches.
 * enabling or disabling Toad commentary during tournament matches.
 * displaying the ball speed in or.
 * player 1 default settings:
 * changing the handedness of the playable character.
 * enabling or disabling gyroscope controls for Zone Shots and Special Shots.
 * use normal or inverted horizontal camera control during Zone Shots and Special Shots.
 * use normal or inverted vertical camera control during Zone Shots and Special Shots.
 * change controls for Trick Shots.
 * change trigger controls for Zone Shots and Zone Speed.
 * change trigger controls for Special Shots and Cancel Charges.

Playable
Mario Tennis Aces features 30 playable characters, consisting of 16 characters available at launch and 14 characters made available post-release as online tournament participation bonuses. Of these characters, Spike, Chain Chomp, Blooper, Boom Boom, Pauline, Kamek, Dry Bones, and Fire Piranha Plant are newly playable to the Mario Tennis series, with Chain Chomp, Pauline, and Fire Piranha Plant also making their overall playable debuts. A number of characters return as playable to the Mario Tennis series after being absent from multiple instalments; namely, Birdo is playable for the first time since the Nintendo 64 instalment, while Koopa Troopa, Koopa Paratroopa, Shy Guy, and Petey Piranha are playable for the first time since Mario Power Tennis. Some characters have unlockable aesthetic variations.

Like in previous installments, characters are split into categories of types. Post-release characters, with few exceptions, each have unique traits.
 * All-Around characters have very balanced stats.
 * Technical characters have good ball control that can easily target corners on the court.
 * Speedy characters have a fast run speed.
 * Powerful characters have strong and fast shots.
 * Defensive characters have a wide coverage.
 * Tricky characters have more curve in their shots.

Mario is the only playable character for the majority of the Adventure mode (Peach is also playable in Lucien Cup Finals), and none of his variations available in other modes are usable. Players can, however, select from multiple rackets as they are unlocked in the mode.

Non-playable characters

 * Piranha Plants
 * Lakitus
 * Biddybuds
 * Yoshis
 * Little birds
 * Rabbits
 * Fire Piranha Plants
 * Munchers
 * Piranha Creepers
 * Nipper Plants
 * Ant Troopers
 * Conkdors
 * Kleptos
 * Big Boo
 * Peepas
 * Bob-ombs
 * Spinies
 * Mechakoopas
 * Monty Mole
 * Lumas
 * Fishin' Lakitu
 * Parabones
 * Bullet Bills
 * Whomp
 * Aster
 * King Bask
 * Lucien
 * Boo Buddies (version 2.0.0)
 * King Boo (version 2.0.0)
 * Fly Guys (version 2.0.0)
 * New Donkers (version 2.3.0)
 * Shy Guy Towers (version 2.3.0)
 * Shield Guys (version 2.3.0)

Audience members

 * Toads
 * Shy Guys
 * Koopa Troopas
 * Koopa Paratroopas
 * Hammer Bros
 * Sledge Bros
 * Goombas
 * Paragoombas
 * Penguins
 * Stone Spikes
 * Fire Bros
 * Boomerang Bros

Courts
Marina Stadium is the starting court, and other playable courts are unlocked for Free Play by completing levels in Adventure Mode. Like in Mario Power Tennis, some courts contain hazards that can be toggled on or off. Prior to version 2.2.0, a court selection screen for Free Play was absent, and courts are chosen at random (however Custom lets the player choose to set the selection of stages).

Story
In some ruins within the Kingdom of Bask, Wario and Waluigi stumble upon a tennis racket named Lucien. As they decide over who gets to use it, Lucien suddenly envelops them both in a mysterious light.

After Mario and Peach beat Bowser and Bowser Jr. in a tennis match and take the championship, Wario and Waluigi arrive with Lucien, offering it to Mario and co. as a present. After Luigi takes Lucien, to everyone's horror, he is immediately corrupted by the racket along with Wario and Waluigi, which causes a big storm on the stadium. Mario and Toad go to Bask Ruins, and after beating a Dry Bones in a tennis match, gain entry to the Temple of Bask. There, a mysterious voice who introduces himself as Aster tells Mario that many years ago, Lucien destroyed the Kingdom of Bask, and its king managed to strip Lucien of its power and divided the power between five Power Stones. Over time, though, the room fell to ruin, and Wario and Waluigi stole Lucien oblivious to its true powers. Aster then tasks Mario to go and get the five Power Stones before Lucien does.

Mario manages to take the Power Stones from Piranha Plant Forest, Mirage Mansion, and Snowfall Mountain; however, the possessed Wario and Waluigi beat him to the Power Stones in Savage Sea and Inferno Island. Lucien then declares a tennis war at Marina Stadium that pits Peach and Daisy against Wario and Waluigi, and Mario against Luigi, which Team Mario wins. Bowser then steals Lucien and returns to the Temple of Bask, where he fuses into Bowcien and challenges Mario to one last battle. Mario wins, destroying Lucien as well as the temple and receiving thanks from Aster before he disintegrates. Everyone then celebrates Mario's victory (though Wario and Waluigi express shame for having to destroy Lucien) as the credits roll.

In a post-credits scene, Mario writes an autograph on the camera, with the marker squeaking the first seven notes of the Super Mario Bros. overworld theme.

Gameplay
In Adventure Mode, Mario has to travel in a hub world and complete missions. While some of them are regular tennis matches, Adventure Mode has a lot of other missions, such as challanges where Mario needs to return the ball until he gets a certain amount of points. It also features boss battles, where different objects need to be shot on bosses with the tennis racket to defeat them. Additionally, the level selection appears to be based on that of the New Super Mario Bros. games, with red panels indicating an unfinished level and blue panels indicating a completed level, with the name of the level being shown when Mario stands on one.

Throughout his journey, Mario can obtain rackets of different stats. All unlocked rackets are stored in a queue that can be viewed in the Stats menu. Each racket unlocked has better stats than the last and takes the front position in the queue. If one of Mario's rackets breaks during a mission, the next one in the queue will take its place until he has no more rackets, signifying that the mission has been lost. By default, these rackets are ordered from the strongest to the weakest (i.e. from the newest to the oldest unlocked), but the player can change their order in the Stats menu.

The following are Mario's rackets, with the mission where they are obtained mentioned under their name.

Bask Ruins

 * Bask Ruins: A Bone to Pick
 * Temple of Bask: An Ancient Trial (accessible in the map prior to clearing "Lucien Cup Finals", which is replaced with "The Final Battle!" though the player can access this level from Adventure Mode's How To Play menu)
 * Temple of Bask Shrine: The Final Battle! (unlocked after clearing "Lucien Cup Finals" and replaces "An Ancient Trial" in the map)

Piranha Plant Forest

 * Piranha Plant Forest: Pipe Gripe
 * Forest Practice Court: Rally Challenge (Beginner)
 * Piranha Plant Habitat: Rapid Fire
 * Forest Edge: Sure Shot Challenge (Beginner)
 * Ancient Altar: Forest Monster
 * Bay Ferry: Battle Boat

Mirage Mansion

 * Mirage Mansion: Malicious Mirrors
 * Mansion Practice Court: Panel Challenge (Beginner)
 * Reflection Room: The Great Mirror Mystery
 * Detour: Rally Challenge (Intermediate)
 * Royal Chamber: All Hail the Mirror Queen

Snowfall Mountain

 * Snowfall Mountain Station: Snowball Fight
 * Snowfall Mountain: One versus...One?
 * Station Square: Sure Shot Challenge (Intermediate)
 * Snowfall Mountainside: Panel Challenge (Intermediate)
 * Snowfall Mountain Summit: Snow Ogre Showdown

Savage Sea

 * Savage Sea Coast: The Sort-Of Sea Monster
 * Savage Sea Bay: The Sea Monster Attacks!
 * Savage Sea: Rally Challenge (Advanced)

Inferno Island

 * Inferno Island: Mechakoopa Crisis
 * Castle Bridge: Sure Shot Challenge (Advanced)
 * Castle Practice Court: Panel Challenge (Advanced)
 * Castle Gates: Defeat Bowser's Minions!
 * Bowser's Castle: Battle the Treasure Guardian!

Marina Stadium

 * Marina Stadium: Lucien Cup Finals

Ruins of Trials

 * Red Trial: Ancient Trial Panel Challenge
 * Green Trial: Ancient Trial Rally Challenge
 * Blue Trial: Ancient Trial Sure Shot Challenge
 * Yellow Trial: Ancient Trial Ring Shot Challenge
 * King's Trial: Last Trial Boss Challenge

Opponents
Unlike their playable versions, they cannot perform Trick Shots and Special Shots, aside from Wario, Waluigi, and Luigi. All of the opponents who were not playable in the initial release are given generic tennis rackets with a black grip and lacking an emblem.
 * Dry Bones - Opponent in "A Bone to Pick".
 * Donkey Kong - Opponent in "Pipe Gripe".
 * Toad - Opponent in "Rally Challenge (Beginner)".
 * Spike - Opponent in "Sure Shot Challenge (Beginner)".
 * Koopa Troopa - Opponent in "Battle Boat".
 * Boo - Opponent in "Malicious Mirrors" and "Rally Challenge (Intermediate)".
 * Shy Guy - Opponent in "One versus...One?" and "Sure Shot Challenge (Intermediate)".
 * Blooper - Opponent in "The Sort-Of Sea Monster".
 * Kamek - Opponent in "Rally Challenge (Advanced)".
 * Boom Boom - Opponent in "Mechakoopa Crisis".
 * Chain Chomp - Opponent in "Sure Shot Challenge (Advanced)".
 * Wario and Waluigi - Opponents in "Lucien Cup Finals" Doubles.
 * Luigi - Opponent in "Lucien Cup Finals" Singles.

Bosses

 * Petey Piranha
 * Madame Mirage
 * Snow Ogre
 * Gooper Blooper
 * Bowser Statue
 * Bowcien

Co-op Challenges
In Co-op Challenges, four players cooperate to obtain a number of points in a limited amount of time. At the end of a challenge, the points earned by all participants are totaled and awarded to everyone. Once the player's total score surpasses a certain amount of points, they unlock a new alternate costume or color for the character that the event is themed around (i.e. Boo in Boo Hunt). In addition, they earn a different title within a Co-op Challenge event for each surpassed goal; for example, the player is a "Veteran Boo Hunter" if they complete the 2,500 point goal in Boo Hunt.

Boo Hunt
Boo Hunt uses Swing Mode controls. In this event, players use tennis balls to hit Boos on the opposing side of the court to eliminate them, earning coins in the process. If the Boos reach the center of the court, they will steal some coins from the group total. Small mirrors that line the center of the court shoot tennis balls for the players to hit. Some Boos have an orange glow, and when a player hits them their next ball will be large, allowing them to hit more Boos at once. There are three stages, and when the group total reaches a certain threshold of coins they can proceed to the next stage when time runs out. Hitting Boos will also increase the Frenzy bar. When the Frenzy bar is filled up, Frenzy Time will activate. King Boo will appear and hover around the court, and all players will continuously receive tennis balls to hit him to earn more coins. He will disappear when either his health bar or the Frenzy bar is depleted.

Different stages have different hazards. Usually, the group of Boos slowly move towards the center of the court. In some stages, they assemble into set formations, and after the players hit the ball at them, they re-assemble into a new formation. Sometimes, the lights turn off, making it hard to see the Boos. Two glow-in-the-dark Boos also appear, and if a player hits one of them, they will be able to control their mirror to shine a light at the Boos that will halt them in their tracks. Other times, pieces of furniture will fly around the room, making it hard to hit the Boos, and Gold Mushrooms will appear, which can be hit to earn coins.

In version 2.1.0, Boo Hunt is permanently added to Special Games in Swing Mode.

Rewards
The player's initial title in this Co-op Challenge is "Beginning Boo Hunter".

Yoshi's Ring Shot
Yoshi's Ring Shot uses traditional button controls. In this event, all four players must work together to reach a high score by hitting the tennis ball through the colored rings. Each ring has four different colors based on the colored Yoshis being playable in this challenge only. If a Yoshi hits the tennis ball through a ring of the same color, it receives more points by doing so. The player can also obtain more points by shooting a ball through multiple rings. The smaller the ring, the more points the player earns. When a Zone Shot or Special Shot is triggered, the player earns double/triple the amount of points. To increase the Frenzy bar, players must keep a rally to increase points and activate Frenzy Time once it is full. During Frenzy Time, all the rings turn into a rainbow color, which are worth more points. In the last 30 seconds of the clock, a special flower-shaped ring appears, which is also worth more points than regular-colored rings. Hitting the flower-shaped ring causes the ring to move to a different location each time, and by increasing combos, players can earn more points and fill up Frenzy bar faster.

In version 3.0.0, Yoshi's Ring Shot is permanently added to the new Ring Shot mode.

Rewards
The player's initial title in this Co-op Challenge is "Hungry Yoshi".

Shy Guy Train Tussle
Shy Guy Train Tussle uses Swing Mode controls. In this event, players have to retrieve as many coins as possible from a band of Shy Guys who have stolen them and are trying to escape by train. To earn coins, players must use snowballs to defeat Shy Guys (who are either on the train or around the train) or destroy the train's freight consisting of crates and barrels. Stationary cannons in the background shoot snowballs for players to hit. There are eight stages, and after the group total reaches a certain threshold of coins, they can proceed to the next stage when time runs out. Hitting Shy Guys will also increase the Frenzy bar. When the Frenzy bar is filled up, Frenzy Time will be activated once the current stage is cleared. Shy Guys will then jump in from the background, forming tall towers by stacking on top of each other, and all players will continuously receive snowballs to hit them to earn more coins. Defeating a tower of Shy Guys and destroying the crate on top of them grants players a key to opening one chest full of coins. Any remaining Shy Guys will leave once the Frenzy bar is depleted. Frenzy Time can be activated up to three times, and each time, one additional tower of Shy Guys is present for players to defeat.

Train layouts and Shy Guys tend to vary slightly between stages, constantly providing players with a different challenge when trying to collect coins. Shy Guys may come in singles or in stacks, as well as larger variants or shield-holding ones; the latter two variations require two hits to defeat them. Some Shy Guys float across the screen with the help of balloons and carry large amounts of coins in crates. Often, players will encounter different kinds of chests as part of the train's freight, which are opened on different conditions. For example, some chests require players to defeat a certain number and color of Shy Guys in order to open them, while other require players to uncover a key hidden inside of a crate.

Each stage also has a certain quota for players to achieve in order to earn extra coins. Once players fulfill a stage's quota, they will earn a large sum of coins which are added to the total threshold. Some crates hold large amounts of extra coins as well as power-ups such as Super Mushrooms, Ice Flowers, or Bob-ombs for players to use. The power-ups can be used to enhance the effect of their snowballs, with the Super Mushroom making the ball larger and able to destroy sturdier crates or barrels in one hit, the Ice Flower splitting the ball into four, and the Bob-omb being able to destroy a large portion of the train's freight.

A large Black Shy Guy appears as a boss in the fourth and eighth stages, wearing a yellow bandana in the former and a red bandana in the latter. Players must defeat him both times in order to successfully complete the Co-op Challenge. As players try to hit him with snowballs, he walks around while occasionally jumping to certain locations on or in front of the train. At one point, he throws Bob-ombs at each of the players which can be knocked back at him to deal more damage than usual. In the fourth stage, players simply have to deplete his entire health bar in order to defeat him. In the final stage, as they fully deplete his health bar, he initiates one final attack in which he throws a Mega Bob-omb that must be knocked back to him by all players in order to defeat him. Once he is defeated, he drops keys which unlock chests that completely fill the threshold of coins needed to complete the stage, thus signaling a successful end to the mission.

In version 3.1.0, Shy Guy Train Tussle is permanently added to Special Games in Swing Mode.

Rewards
The player's initial title in this Co-op Challenge is "Fledgling Ranger".

Stage layouts
The following gallery shows possible stage variations in this Co-op Challenge.

Pre-launch demo
Prior to the game's release date, a free demo titled Mario Tennis Aces: Online Tournament Demo was released on the Nintendo eShop on May 24, 2018. This demo included a pre-launch online tournament, as well as the ability to practice with CPU players. The tournament allowed players to play as Mario, Peach, Yoshi, and Bowser, with Waluigi, Toad, Spike, Rosalina, and Chain Chomp becoming available as players earned points, for a total of nine playable characters. All tournament participants could receive an alternate costume for Mario that dresses him in his usual clothes (effectively making him appear identical to his appearance in Mario Tennis: Ultra Smash), usable in the full game.

April–May 2019 Special Demo
Another free demo titled Mario Tennis Aces: Special Demo or Mario Tennis Aces: Special Online Demo was downloadable between April 26 and May 3, 2019, but only playable from April 26 to April 28, 2019. Upon downloading it, the player received a code for a free seven-day subscription to the Nintendo Switch Online service. Compared to the previous demo, this demo had some changes and additions. It featured a different title screen, different unlockable characters, simple class, Co-op Challenge mode (where Yoshi's Ring Shot was playable, and the blue, red, and yellow Yoshis could be unlocked for use in both the demo and the release version), and other features introduced in the full game as of version 2.3.0 (new adjustable control options and a revamped online tournament). The character unlock criteria was also changed, requiring the player to simply play a set number matches (including both computer and online matches) to unlock each character instead of earning points in tournaments. Likewise, Mario's alternate costume could be unlocked by participating in a match either online or offline.

Update history
Mario Tennis Aces has received multiple updates after launch, which added new content, character balancing, and bug fixes. Notable changes unlisted in the patch notes are written in italics.

1.1.1
An update was released on June 28, 2018 (PT). The following changes were made:

1.1.2
An update was released on July 19, 2018 (PT). The following changes were made:

1.2.0
An update was released on July 31, 2018 (PT). The following changes were made:

2.0.0
An update was released on September 19, 2018 (PT). The following changes were made:

2.0.1
An update was released on October 10, 2018 (PT). The following changes were made:

2.1.0
An update was released on November 30, 2018 (PT). The following changes were made:

2.1.1
An update was released on December 13, 2018 (PT). The following changes were made:

2.2.0
An update was released on January 30, 2019 (PT). The following changes were made:

2.3.0
An update was released on February 28, 2019 (PT). The following changes were made:

3.0.0
An update was released on April 14, 2019 (PT). The following changes were made:

3.1.0
An update was released on May 31, 2019 (PT). The following changes were made:

Critical reception
Mario Tennis Aces received generally positive reviews from critics. Praise was directed at the visuals and many welcomed new additions of gameplay, but minor criticism was directed at customization and the story mode, with some considering the latter not being rewarding or satisfying enough. The Swing Mode also received mixed reception, with points of contention directed at its responsiveness. The game currently holds a score of 75 on Metacritic based on 84 reviews, and a score of 73.38% on GameRankings based on 37 reviews.

Tristan Ogilvie of IGN gave the game a score of 7.5/10, praising the visuals, the court gimmicks, and the multiplayer mode, but criticized the story mode (considering it bare-bones, with nothing making it a fresh and satisfying experience), and also criticized the way local multiplayer works, stating "The biggest problem with Mario Tennis Aces[s] Adventure mode is how poorly it incentivises you to keep playing. I had completed all 27 of its levels and unlocked all of its courts and rackets by the time I was on level 34, which was around a half a dozen hours of game time. Out of curiosity, I replayed a number of the challenges and boss fights several more times over to grind my way up to level 55, but was rewarded with absolutely nothing aside from incremental boosts to Mario's stats, thus making the existing challenges even easier. With no New Game+ or more challenging versions of its levels to unlock, or even the option of playing through it with a different character, Mario Tennis Aces[s] Adventure mode becomes increasingly simple and repetitive the more time you put into it." In a more positive review, Mike Diver of Nintendo Life gave the game an 8/10, praising what he believed to be vast improvements over its Wii U predecessor Mario Tennis: Ultra Smash, stating "Where [Mario Tennis:] Ultra Smash's extras were a pure Monkey Island's worth of living without that particular piece of junk – here's your context, kids – [Mario Tennis] Aces stuffs its kit bag with activities until the zip's positively pinging off across the locker room like a smartly volleyed can of energy drink. Not everything is evenly fleshed out, but whatever your preferential way to play, there's plenty to get stuck into, both solo and with pals." In a slightly more lukewarm review, Justin Clark of GameSpot gave the game an 7/10, praising the game's new playing mechanics over past games as well as the story mode's incentive to teach players of the new mechanics, but had mixed to somewhat positive feelings about the story mode, stating "The story itself is ridiculous, but ridiculous in that very specific, quirky way Nintendo has been getting away with for decades. During the Mushroom Kingdom's annual tennis tournament, an evil tennis racket--yes, really--named Lucien takes possession of Luigi and flies off to find five Power Stones that will help him take over the world." He was also more critical of the online play, panning a stark lack of features as his main issue.

Sales
By December 31, 2021, the game had sold 4.28 million units worldwide, making it the best-selling game in the Mario Tennis series.

Promotion
The Play Nintendo website features a skill quiz, a personality quiz, and an activity based on Mario Tennis Aces.

Pre-release and unused content
The Special Chance Shot markers from Mario Tennis: Ultra Smash, needed to perform the Ultra Smash, were featured in the announcement trailer. The animation Mario performed there was also the same one used for those kinds of shots. In the final game, however, those Chance Shot markers were rather replaced with a rotating star marker, similar to the ones featured in Mario Tennis and Mario Power Tennis, and Zone Shots replaced Ultra Smashes, while retaining their character animations at least in the case of Mario.

The HUD icons for Mario, Luigi, Wario, and Waluigi originally used their traditional outfit. Various pre-release footage of Marina Stadium had different cosmetic screen animations in banners, and the character name in the court's floor had a different font (this font is used in the final game when playing in online modes, with the user nickname on the floor). The Ancient Altar court used in Forest Monster was originally a selectable court.

Originally, Daisy's final entrance pose showcased her with her mouth closed via a Nintendo Treehouse Log post. In the final game, her mouth is open.

References to other games

 * Super Mario Bros.: A cutscene after the credits shows Mario drawing his cap on the camera lens with a crayon. The rubbing sounds are the first few notes of the overworld theme.
 * Super Mario Bros. 3: Boom Boom's running animation is flailing his arms while facing the opponent, mirroring his sprite animation from this game.
 * Mario's Tennis: This is directly the first time in the Mario Tennis series (and the second time overall) that Mario and Luigi wear short-sleeved T-shirts and shorts and athletic shoes as their default outfits instead of their standard overalls. However, here they wear visor versions of their signature caps, while in Mario's Tennis, they wear their usual caps.
 * Super Mario 64 / Super Mario 64 DS: The design of Snow Ogre highly resembles that of Eyerok. Also, the music that plays while battling Bowcien is a variant of Bowser's battle theme and the Bowser levels from this game.
 * Super Mario Sunshine: The sounds that Piranha Plants make are reused from this game.
 * Mario Power Tennis: The announcers' voice clips and the sound Chain Chomp makes are reused from this game. Many characters' voice clips from this game are reused for their Special Shot animation.
 * Mario Party 6: Mario's artwork from this game is reused on one of the large banners.
 * New Super Mario Bros. U: The Koopalings' airships from this game appear flying in the background of Savage Sea. The large claw arm Bowser Jr. uses for his Special Shot also returns from this game. Boom Boom's losing animation is similar to his animation after getting stomped from this game.
 * Super Mario 3D World: Several enemies from this title appear in the background of the courts, such as Piranha Creepers and Conkdors. Rabbits also appear and retain their design from this game.
 * Mario Tennis: Ultra Smash: Marina Stadium bears a striking resemblance to the stadium found in this game. Character models, animations, and voice clips are reused from this game. Mario Tennis Aces artwork of Yoshi is also originally from Mario Tennis: Ultra Smash, albeit with a different tennis ball.
 * Mario Sports Superstars: Character shield emblems are inspired and derived from this game.
 * Super Mario Odyssey: Pauline's voice clips are reused from this game. For her Special Shot, "Jump Up, Super Star!" plays in the background and several New Donkers appear, as she summons a building resembling New Donk City Hall.

References in later games

 * New Super Mario Bros. U Deluxe: Toadette's voice clips are reused in this game.
 * Mario Kart Tour: Some of Birdo's voice clips are reused in this game.
 * Mario Golf: Super Rush: The Toad commentators from this game return, once again giving commentary during matches. Many playable characters now wear proper golf outfits, similarly to how various characters wear proper tennis outfits in Mario Tennis Aces. Peach's Special Dash and Special Shot use a ribbon similar to the one found in Peach's Trick Shots and Special Shot from Aces.

Trivia

 * Starting with this game, Simplified Chinese names of many common enemies were overwritten with their Traditional Chinese counterparts, like Koopa Troopa (喏库喏库 to 慢慢龟), Boo (嘘嘘鬼 to 害羞幽灵), Dry Bones (枯骨怪 to 碎碎龟), Blooper (乌贼怪 to 鱿鱿) and Lakitu (朱盖木 to 球盖姆). However, Simplified Chinese names of major characters (Mario, Princess Peach, Bowser, etc.) and Shy Guy remained unchanged. Common enemies whose names did not appear in this game would witness their name change in the coming Super Mario Party, Super Smash Bros. Ultimate, New Super Mario Bros. U Deluxe and Super Mario Maker 2, with Hammer Bro (锤子兄弟 to 铁锤兄弟) and Goomba (栗子小子 to 栗宝宝) as an example.