I think Tarver over Roy is the only one that rivals it. Both had dramatic endings; Tarver's ko was more shocking because of Roy's aura but JMM's came on the back of three controversial fights and he finally slayed the dragon. I'm not sure which was greater but they're the two that stand out to me. Morales' victory over Pac just months after losing to MAB was superb and gave him a sense of redemption but the ending of those other fights puts them over the top.
There were lots of people who said Marquez would win especially from previous fights that could of went either way.
But how big an underdog the guy was doesn't matter, only how good the guy he beat was, that's what we are talking about here. (you still may be right, though, I don't know)
I disagree . B Hops achievement of becoming the oldest champion in ANY sport in history is a much bigger win than Marquez knockout win over many . Pac has been knocked out before . Its been done already . What Hopkins recently accomplished will not be repeated .
Its a great win in paper but in reality it is treated like many other flash knockouts by a fighter who was getting beat badly. Rahman's win over Lewis is on paper a great win but most dont give it much credit.