Originally Posted by Low Blow Combos
I'll counter that with this:
How does Hearns break the Mayweather defense?
Hagler beat Hears and he didn't have half of the skillset Mayweather does.
Hagler went to war with Hearns. He had the tools (and the toughness) necessary to do that and win, but he still had to take some good punches along the way. Hagler's style is nothing like Mayweather's style, nor are they similar in terms of physical qualities.
Mayweather has a very good defence, one of the best I've seen, but he's vulnerable to jabs. Hearns has a great, long and fast jab, and he would use that to set up his powerful straight right. He would have trouble hitting Mayweather, just like all fighters, but he would get through at points due to his combination of boxing ability, handspeed and reach. Mayweather could not walk him down and go to war, because Hearns is too dangerous to do that unless you have power and you're willing to take hard, potentially knockout shots on the way in. Mayweather would have to stay on the outside and make it a boxing match, but he would have trouble landing at that range while trying to deal with the constant jab and right hand from Hearns. Hearns is also more active, and in a close round (even if Mayweather is rolling or evading a lot of punches) that would swing it in his favour. He can't box with Hearns on the outside due to these difficulties, and he certainly can't try to walk him down and KO him, as that would make matters worse. It's just a very bad fight for Mayweather.