Pac beating and stopping Oscar was impressive to start with until it was revealed Oscar had made a massive mistake in coming down to Welter for the 1st time in about 9 years and had to be rehydrated via intra venus just before the fight. Mayweather had already beaten Oscar himself at Oscars comfortable weight 154lbs where he was regarded as number 1 and WBC champ. And many feel Pac lost to Marquez both times where against Mayweather Marquez couldn't win a round let alone the fight so im going with Mayweather.