Which was the last fight Oscar was in his prime?

Mosley 2.... but he was still in very good form for Mayorga and Mayweather albeit past his prime.

he looked like **** at MW cause it was MW and he shoulda never been fighting there. He put in a solid performance vs Mayweather, after that I don't think he had the motivation anymore as he got busted up by little Stevie Forbes and shoulda called it a day after getting a last W on his record but guess he figured Pac was too small to **** with him regardless, pretty dumb move.