Virtua Tennis 3

There are 12 different training games to be completed. These are (in alphabetical order):
-Alien Attack
-Avalanche
-Balloon Sniper
-Bull's Eye
-Count Mania
-Court Curling
-Drum Topple
-Feeding Time
-Panic Balloon
-Pin Crusher
-Prize Defender
-Super Bingo
To complete a training game, you must beat or obtain the target score in the limited time or amount of balls you are given. To unlock all of the training games (you start with 5), keep playing the training games you have, I found this to be a faster method of unlocking them, although they all will unlock over time. Play through all the training games at level 1, to make them easier to complete. After you successfully clear the 12th training game, the achievement will unlock when you start another match, whether the match you star is a training game, or just a match of tennis, the achievement will not unlock when you actually beat the 12th training game.