Rainbow Flutter

From the Super Mario Wiki

Rainbow Flutter is the Offensive Power Shot used by Yoshi in Mario Power Tennis. It involves Yoshi doing a Flutter Jump in the air and then hitting the ball with a rainbow following it. This may be the inspiration for the Flutter Dunk from Mario Hoops 3-on-3.

This power shot is able to hit the ball, even if it's very high in the air. In fact, it's the only Offensive Power Shot that's capable of doing this.

Offensive Power Shots Mario Iron Hammer Bowser Fire Breath Luigi Squeaky Mallet Bowser Jr. Magic Paint Princess Peach Super Peach Spin Boo Boo Blast Princess Daisy Wonder Flower Fly Guy Tornado Twist Wario Thunder Cast Shot Diddy Kong Acrobatic Banana Waluigi Whirluigi Paratroopa Energy Ball Yoshi Rainbow Flutter Wiggler Anger Management DK Barrel Cannon Blast Petey Piranha Sludge Racket Shy Guy Lightning Spear Koopa Troopa Water Bomb

Defensive Power Shots Mario Spin Jump Return Bowser Spinning Shell Dash Luigi Poltergust Return Bowser Jr. Rolling Brush Return Princess Peach Sweet Kiss Return Boo Boo Brigade Return Princess Daisy Flowerbed Return Fly Guy Tornado Return Wario Ultra-Hand Return Diddy Kong Barrel Jet Waluigi Swimming Return Paratroopa Sky Dive Yoshi Rolling Egg Return Wiggler Flutter Return DK Boomerang Banana Return Petey Piranha Piranha Swingback Shy Guy Spear Dance Return Koopa Troopa Water Shell Dash