The fighters who've lost to Floyd Mayweather explain why he's so impossible to beat

Floyd Mayweather Jr. is widely regarded as the best fighter of his generation and one of the best defensive fighters of all time.Over the years the fighters who've lost to Mayweather have spoken about his boxing brilliance in glowing terms, and explained what makes him so hard to beat.There's a radical juxtaposition between Mayweather's persona out of the ring (obnoxious, offensive, appalling) and his style within it (calm, intelligent, pragmatic).