I think you look at the difference in the fighter, Mayweather ability to move, and throw combinations decreased significantly as he went up to welterweight, it reminded me of Roy Jones when he took on John Ruiz. Ricky Hatton retained virtually the same speed in every department, he looked the same. WHen a guy like Mayweather really has to bulk up to make welterweight then he is the smaller guy, I mean he was a small junior welterweight, and If you look back people used to use the arguement that Hatton would beat Floyd around the Hatton-Tszyu and Mayweather-Gatti because Mayweather never delt with strength or size like HAtton brought to the table.

Hatton's size is misleading because he is short, but like Miguel Cotto(to a lesser extent), and Joshua Clottey, he is has a very condensed body whereas Mayweather has a lean body, longer body. WHen Mayweather went up to welterweight he blew up in muscle size, but that isn't the same as natural strength and size, as Mosley-Wright would indicate. Mosley was naturally stronger, but in the ring he wasn't stronger because that strength was purely explosive fast fibers, in terms of retention of strength Winky had the upper edge. We saw it with Calzaghe against Lacy where he muscled Lacy around the ring, not jsut outboxed him. There were a few times in the Hatton-Mayweather fight where Hatton easily maneuvered Mayweather, and he no problem keeping Mayweather on the ropes, but like against Corrales the longer Mayweather was pot shotting Hatton, just like he did to Corrales it weakens them. Mayweather wasn't the stronger man, but he was in better shape(which is better than anyone's in boxing), and he let Hatton wear himself out.