How do you use a haymaker in fight night round 3?

In Fight Night Round 3, to throw a haymaker, you need to press the right stick in the direction of your opponent while simultaneously holding the left trigger (L2 on PlayStation or LT on Xbox) to enter the power punch mode. This will unleash a powerful punch that can potentially knock out your opponent. However, be cautious, as haymakers are slower and can leave you vulnerable if missed. Timing and positioning are key to effectively using this move.