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The Rainbow Save is a defensive Power Shot in Mario Tennis: Power Tour. It is not used by any character in Power Tour mode, and can be unlocked for usage on the player character by having the following PS stats: 10 Speed, 10 ESP, 10 Spin and 8 Balance. It is generally considered to be the final unlockable defensive power shot.
The user will generate a small cyclone, bringing the tennis ball towards the racket, while the user spins on the spot. The user will then hit the tennis ball, which will travel forwards, leaving a trail of semi-circular rainbows. Receivers will not receive a negative effect, should they return the ball.
"Suck the ball in with a beam of light and return it with a drop."