Most impressive 1st round KO.

[young_robbed]

Not the best, but Norton's KO over Bobick when Bobick was supposed to be the next great white hope.

[Great John L]

How about Shavers-Quarry?

Other good ones are
Shavers-Norton
Tyson-Frazier
Cooney-Norton
Holmes-Frazier

[Wild Blue Yonda]

Of those listed, I would have to say Louis-Schmeling, though Liston-Patterson (I assume you mean the first fight) is probably the most under-appreciated.

A very good one from around the same time is Johansson-Machen, when you consider that Johansson wasn't considered (& IMO, really wasn't, period) at such a high level as to do what he did to a gifted & smart technician like Machen (who lasted the distance with the aforementioned Liston). That was an outstanding showing from the future Champion, to beat a very respected & formidable contender so rapidly & decisively.

[Kid McCoy]

Of those listed, I would have to say Louis-Schmeling, though Liston-Patterson (I assume you mean the first fight) is probably the most under-appreciated.

A very good one from around the same time is Johansson-Machen, when you consider that Johansson wasn't considered (& IMO, really wasn't, period) at such a high level as to do what he did to a gifted & smart technician like Machen (who lasted the distance with the aforementioned Liston). That was an outstanding showing from the future Champion, to beat a very respected & formidable contender so rapidly & decisively.

I agree. Machen never knew what hit him. It's quite a disturbing KO to watch. Ingo was otherwise a fairly average fighter but he did have a brilliant right hand. Angelo Dundee said Ingo threw his right the way a trainer wished his fighter would throw it. Machen fought Sonny Liston and Cleveland Williams in their prime and also a young Joe Frazier, and none of them got to him the way he did. A year later he surprised Floyd Patterson with the same punch.

[Scott9945]

Louis-Schmelling, and I don't think it's even close.

[Dodger07]

Louis ko of schmeling has to be 1 because of its significance that trancended boxing

[Emon723]

I seem to be enjoying watching this fight over and over on Youtube.

Danny Green KO1 Roy Jones!

[IronDanHamza]

All great KO's but the winner stands alone, Louis-Schmeling 2. The way Joe came back from his first loss with was a dominant stoppage, to KO Max the way he did, it's just historical beauty.

[Dodger07]

Taking into account the level each guy was fighting at when the fight took place.

Tyson-Spinks
Ali-Liston
Liston-Patterson
Louis-Schmeling
Marciano-Walcott

Any others?

Edited: Cuevas-Hearns was a 2nd round KO, I forgot.

[Dodger07]

Taking into account the level each guy was fighting at when the fight took place.

Tyson-Spinks
Ali-Liston
Liston-Patterson
Louis-Schmeling
Marciano-Walcott

Any others?

Edited: Cuevas-Hearns was a 2nd round KO, I forgot.