Mosley didn't allow Vargas to do anything because he had something new Vargas never looked for..the left hook. You can see Vargas watching Mosley's right hand all night and leaving himself wide open for the left each time, even when he tried to jab he was watching Mosley's right which is how Mosley was able to step back and land a left hook that Vargas never saw, he was so focused on the right hand that he forgot the left hook of Shane is his best punch. Much the way Robinson knocked out Fullmer Same kind of left hook, picture perfect