Fights where he looked the best: Corrales at 130, Ndou at 135, Gatti at 140, unsure about 147, Canelo over 147 Worst. Chavez at 130 (by far the worst fight of young Floyd), Sosa at 135, none at 140 or over 147. Maidana I at 147
I actually thought Mayweather looked good vs Jesus Chavez it was an exciting fight he stood in the trenches and outfought Chavez up close and beat him up in the later rounds those uppercuts were brutal. Best performances Super Featherweight: Diego Corrales = A boxing masterclass. Lightweight: Phillip Ndou = An aggressive Mayweather showing his full offensive arsenal. Jr Welterweight: Arturo Gatti = Same as above. Welterweight: Ricky Hatton = A rare stunning KO for Mayweather at Welterweight. Jr Middleweight: Canelo Alvarez = A masterclass against a much younger opponent. Worst performances. Super Featherweight: Gregorio Vargas = Mayweather broke his hand and was ruled officially down for the 1st time in his career. A bit of a flat performance from Mayweather not one of his best fights at a very good weight for him. Lightweight: Jose Luis Castillo 1 = Since alot of people felt Mayweather lost this fight I think you have to mention it Castillo bossed the 2nd half of the fight. Jr Welterweight = I don't think Mayweather had a bad performance at this weight he only had 4 fights at the weight and they were all stoppages. Welterweight: Marcos Maidana 1 = Has to be this one because of how close it was the only other real competitive fight Mayweather had at Welterweight was Judah.
I think you're thinking of his fight with Famaso Hernandez at 130. He shut out Goyo and had him on floor for a brief count.