The real comparison will be considering Mosley along side Cotto and Clottey. On the Mayweather side of the argument there will be fans out there saying that beating Mosley is at least as impressive as beating Cotto, and that Clottey isn’t even a factor. A decent top ten win, but not really relevant when discussing the very top of the rankings tree. In most ranking systems, Pacquiao attained his win over the number two ranked welterweight at the time in Miguel Cotto. Going on rankings alone then he still has a more impressive win than Mosley. There is also the argument to be made however that Cotto was past his best after the beating he took from Antonion Margarito. Then again Mosley at 38 probably isn’t at the peak of his powers either.
A case can be argued for either, but the best way to work the rankings out after May would be for Pacquiao to fight the winner of Mayweather vs Mosley. Given that it probably won’t happen if Mayweather wins, then the only other way to guage their respective achievements will be to wait and see who both fight over the next year or so. There aren’t that many big names at welterweight right now that they can both continue to fight top guys, so sooner or later one of them will be visibly fighting lesser competition than the other.
A wild card entering the discussions sooner or later will be Antonio Margarito, who looks set to craw his way back into contention license from the CSAC or otherwise. A win over him for either man would clearly place them at the top of the rankings pile. Also there is Andre Berto to consider, at the moment a fringe contender but still undefeated and perhaps after another fight or two a force in the division.
Paul, Pittsburgh: “Pacquiao is a cheat and Floyd is a coward so neither of them deserves to be the top ranked guy. Hopefully someone comes up through the ranks and beats both of them”
James, Pittsburgh: “Mayweather can never be ranked higher than Pacquiao without fighting him, he’s too inactive, he doesn’t finish fighters that Pacquiao would have and he’s only fighting Mosley because he had to”