If you win the World Champion title you will get at secret boxer that you can
use in Exhibition mode. If you get all champion titles you will get all secret
During a bout in Road to World title or tournament mode; Hold L1 + L2 + R1 +
R2 and press X. Then press X again to display a loading screen instead of the
game trivia. Now press X again to win the current bout.
Thanks to Revolution reader Henrik Pedersen!