To unlock the following courts win the following matches.

Court	How to unlock
Aloha Beach Tennis Court	Beat Ashley (aka Yelena) in Beginners Class.
Grand Palais Indoor Court	Beat Kent (aka Ryu) and Will in Japan Class.
Miyabi Tennis Grove	Beat Cody (aka Yuki) in Semi-pro Class.
Nakagawa River Courts	Beat Jun and Ashley (aka Yelena) in Amateur Class.
Queen's Tennis Garden	Beat Carol and Gloria in World Class.
Temple of Olympia Court	Beat Momoko in Semi-pro Class.
West Prairie Tennis Court	Beat Big Chief (Rock Bull) in Pro class.
Wild Green Tennis Court	Beat Jun and JJ in Beginners Class.