Battle the Treasure Guardian!

Battle the Treasure Guardian! is the twenty-sixth mission in Mario Tennis Aces, taking place at Bowser's Castle.

Layout
Mario and Toad enter Bowser's Castle, certain that Lucien's puppets will steal the Power Stone if they do not act fast. They find that a Bowser Statue guards the Power Stone.

In this mission, Mario must defeat the Bowser Statue within 300 seconds. In battle, the Bowser Statue deploys a forcefield around itself, and launches sets of three fireballs at Mario which must be knocked back; if a fireball is not lobbed back, it becomes a stage hazard. The Bowser Statue will then fire a laser beam that sets the ground ablaze, finishing by firing a giant purple fireball which can be knocked back to deal lots of damage. The Bowser Statue will repeat this process until it is out of health, in which Mario must avoid the oncoming meteors to perform a Zone Shot at the statue's mouth. The statue will then repeatedly shoot streams of fire at Mario, then repeat its ball-serving mechanics, except it will more evenly space out the fireballs it shoots. After Mario fires a Zone Shot at it a second time, it will shoot streams of fire again, except perform a sweeping motion with them. It will then repeat the same ball-serving mechanics it used in the second phase.

Afterwards, Mario attempts to obtain the fifth Power Stone, only for it to be stolen by a corrupted Wario and Waluigi, same as the fourth.

In-game text

 * "Defeat the boss of Inferno Island within the time limit!"