Sometimes, a fighter who's not considered a hard puncher will win a fight by knockout because he landed a perfect punch right on the button. The best example I can think of is Michael Nunn's shocking first round KO of Sumbu Kalambay. Nunn wasn't really known as a puncher, but he landed a beautiful straight left that knocked Kalambay out cold.
Wow, there was a time when a thread like this wouldn't have reached the second reply without an Ottke vs. Mundine shout ...but then, it has been a couple of decades now and neither is exactly the sort of fighter younger fans will delight in performing a deep-dive on. So you either remember it, or - you don't.