Duran takes him and KO's him in the later rounds. Duran was too much of a beast at 135, and would have had anyone who wasn't a really intelligent boxer in trouble. JCC would have got involved just how Duran would have liked it, and Duran's power would have carried him to victory. There's very few lightweights in recent history that I could see beating Duran. The only ones where I could see it maybe happening is Pernell, Floyd & maybe Shane Mosley at 135, but the first two it would be the slickness and being able to quickly get in and out, almost how Leonard did in their 2nd fight, and avoiding Duran to get a decision.