So, I had this thought, that I don't know if anyone has mentioned. If you click on the 2 question marks in tennis at the beginning, you can play against yourself, and have you controlling each miis, so you can guarantee a perfect game. Respond to me if anyone has mentioned this before. Thanks!

The rules specify that you “must play against CPU in Tennis, Baseball, and Boxing” and win depending on the category. I believe this is applicable to all categories

I had just seen that. Thank you for the clarification.