It's divided in series of 15 tie breakers each. At round 15, you face giant Bowser, and from rounds 16-29, the wacky courts start showing up. At round 30, you face giant Dry Bowser. Beat him to get the credits. Knockout Challenge loops after that except facing star rivals and using the unlockable courts from the get go, with increasing difficulty (think star tourneys of 64 and GCN Mario Tennis)