I'd put my money on Cerdan, whom I rate very highly as a fighter. Rocky was one of those real action men in the ring. He was a real bull in there and always came to fight, and was blessed with a big punch. However, as the Zale fights show, he wasn't known for his defensive qualities in the ring and although tough, he was not blessed with immense durability. Cerdan in my mind, had an equally good punch but his skills were much more refined than were Rocky's. He had better movement, a better defence, punched better in combination and was arguably as tough - if not tougher -than Rocky. I think it would be a very close fight for five or six rounds, but Cerdan's better overall skills would enable him to exploit the gaps in Rocky's defence for a ninth round KO win. Grziano would probably go down swinging though.
