Mayweather IMO had the most impressive performance against Oscar. He was way smaller. He outboxed OScar, made a very fast man miss almost every shot. Hopkins had a close fight with Oscar for the first few rounds, and not until he found his right hand did he begin to dominate Oscar. I think Mayweather had him figured out from the begining.

Also I havent' seen Oscar be so sharp defensively as he was against Mayweather in his entire career. I have watched every fight of his, and he never did the two things he did against MAyweather
1) He didn't try to outbox Mayweather like he did against Mosley, and
2) Even though he pressured Mayweather, he didn't sacrifice his defense which was most notable against Forbes in their fight, against Mayweather he knew Mayweather had a low output and would wait for Mayweather to throw something, or follow behind the jab, but once again Mayweather was able to counter him very effectively with the right hand.