If you start the game without a controller plugged in, Waluigi flies away with the N64 while Luigi chasing after him with a controller.
This game is Waluigi's first appearance, and Paratroopa's first appearance as a playable character.
If Mario is not one of the characters on the court, he will appear as the referee. However, if Mario is one of the players, the referee will be either Toad or a blue version of Mario. The latter is a reference to Tennis for the NES, where Mario also wore blue as the referee.
The ring tournament mode was removed from the Virtual Console version of the game for unknown reasons.
Alex, Nina, Harry, and Kate are no longer playable in the Virtual Console version of the game. None of the character's personalized courts (excluding Donkey Kong's) can be unlocked either. This due to the game needing to be connected to the Game Boy Color version of Mario Tennis to unlock this content, which the Wii cannot do.