Well, Pac fought Marquez at different weights and P4P they are fair opponents for one another. Marquez was just far too small and unprepared to fight Mayweather who had been at the weight for a long time. Of course it would be bizarre for Mayweather to fight Marquez 4 times.

In terms of common opponents, is it not a fact that mini Manny has also beaten them far more ably and easily than Floyd who has been WW at above for a very long time? Not bad for a tiny little man. Cotto pounded. DLH dusted. Mosley massacred. Hatton hammered. But Marquez is to define this fight? I'm not so sure that is the case.

Manny was finally doing a number on Marquez in the 4th fight and just got sloppy. Manny has also shown more strings to his bow in recent years. Mayweather on the other hand is losing his legs and is getting tagged a lot. He cannot afford to have no legs and get tagged too much against Manny.

I think output and activity will be the difference in this one. Maybe a bit like Calzaghe/Hopkins except Pac can hit harder and Mayweather will perhaps try to spoil even more.