There are so many great 1 punch KOs it's hard to pick one. Robinson vs Fullmer 2, Marciano vs Walcott 1, McCallum vs Curry, Patterson vs Johansson 2 etc.
Not a 1 punch knockout but one of the best punches I've seen was in Curry vs McCrory, Curry landed a perfect left hook that knocked down McCrory, McCrory was badly hurt and shouldn't have been allowed to continue but Mills Lane let him continue, he didn't get far.
I think it does count as aone punch KO because, even though Duran had been dropped in the first round, right before he got dropped, he seemed okay because him and Tommy were both throwing shots at each other, then he goes against the ropes and gets DESTROYED by a right hand.
Herol Graham v Julian Jackson
Monster KO, and Jackson was getting the **** beaten out of him
This is, I think, the absolute definition of the greatest one punch KO in the sport. Jackson was of course probably the biggest puncher that boxing has ever seen and this fight typifies his power.
Herol was one of the great underrated defensive fighters of that time. A time when the middleweight division was certainly full of some of the best fighters that have been in and around one division ever. Anyway, Jackson was getting the first true whipping of his career and his corner gave him one more round and they were going to stop it. Of course, what happened next is amazing but very sad as well. Right near the end of the round Graham drops his left as Jackson swings wildly with that monstrous right and lands it perfectly right on the very, very tip of the chin. No one in any weight division could have survived that punch!
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