Floyd Mayweather will face Andre Berto in a welterweight title fight Saturday on pay-per-view at the MGM Grand Garden in what he says will be his final match. Mayweather, who frequently refers to himself as "The Best Ever," is 48-0 and is better than a 30-1 favorite to top Berto. Whether Mayweather is the greatest fighter who ever lived, regardless of weight, is something that will never be proven and is no more than a matter of opinion.