From Wikipedia (abridged)
Fight Night Round 2 is the sequel to EA Sports' Fight Night 2004. It was released for PlayStation 2, Xbox, and GameCube consoles in 2005. It was the only Fight Night game in the series to be released on GameCube. The GameCube version contains the SNES version of Super Punch-Out!! along with its protagonist as an unlockable character.
Total Punch Control, a control scheme introduced in Fight Night 2004, returns in Fight Night Round 2. With Total Punch Control, movement and most maneuvers, including punching, leaning and blocking, are performed with the left or right analog sticks, modified by the left or right triggers. For example, with the default controller configuration, moving the right thumbstick up and to the left will cause the fighter to throw a straight punch with his left hand, while holding down the right trigger while performing the same movement and then holding will cause the fighter to raise his guard to the left side of his head, ready to attempt a parry.
Fight Night Round 2 expands upon the Total Punch Control scheme with the addition of another feature, the EA SPORTS Haymaker. An EA SPORTS Haymaker is a more powerful version of one of the basic power punches (hooks and uppercuts) and is performed by pulling the analog stick back before performing the movements for a regular punch. If it connects, a Haymaker causes quite a bit of damage, can stagger the victim and may cause an instant knockdown, regardless of the victim's health or stamina status. If blocked, the Haymaker does very little to no damage while consuming a great deal of stamina from the attacking boxer. If parried, the attacker is pushed off-balance and is left vulnerable to a Haymaker or combination attack.