So we are either talking about Kostya or Floyd. Either way, I'm not sure Zab was their best win. In the case of KT, he faced an undefeated 140lb version of Judah. Peoples perception of Judah at that time was totally different, and KT had plenty of other wins of that were equal or better. As for Mayweather, his wins over Chico, Castillo, Oscar, and Hatton are better wins than the Judah win.