Unlock Shyguy
Beat the Star Cup Singles Tournament with any character to unlock Shyguy.

Unlock DK Jr.
Beat the Star Cup Doubles Tournament with any character to unlock DK Jr.

Unlock Baby Mario/Yoshi Court
Beat the Mushroom Cup Singles Tournament using Yoshi to unlock the Baby Mario/Yoshi court.

Unlock Donkey Kong Court
Beat the Mushroom Cup Singles Tournament using Donkey Kong to unlock the Donkey Kong court.

Unlock Super Mario Bros. Court
Beat the Mushroom Cup Singles Tournament using Mario to unlock the Super Mario Bros. court.

Unlock Wario/Waluigi Court
Beat all of the Doubles Cups using Wario to unlock the Wario/Waluigi court.

Unlock Super Mario Bros. Court #2
Beat all of the Doubles Cups using Mario to unlock the Super Mario Bros. Court #2.

Unlock Birdo/Yoshi Court
Beat the Star Cup Doubles Tournament using Birdo to unlock the Birdo/Yoshi Court.

Unlock Piranha Plant Court
Beat any court in the Piranha Plant Challenge (return all 50 tennis balls) to unlock the Piranha Plant Court.
Note: This court is only available for use in the Piranha Plant Challenge.

Unlock Special Cups
Beat all of the Singles Tournament Cups with all of the characters in the game to get the Special Cups.
Note: To access the Special Cups, hold R to give your character their handicap when selecting them.