Impossible to tell, really. It shows how great Duran was that as a former lightweight champ he could beat a fully-fledged world-class middleweight. But we had a picture of Duran at welter, light middle and middleweight already before he met Barkley. Leonard was a lightweight and then a past-prime welter - not much to judge him on as to whether he could handle someone of Barkley’s size.
