Interesting question. The second half of Ali's double jab was often a backhand jar, flicked in by a straightening from the elbow following the recoil of the first. If it looks picturesque, and gets delivered with sufficient speed and sleight of fist, it gets admired and praised instead of penalized. Muhammad did a lot of it in the middle portion of his rematch with Jerry Quarry. The backhand was certainly an integral part of Chuck Wepner's vast arsenal of kicks, rabbit punches, glove heels, lace rakes, elbows, shoulder bumps, foot stomping, kicking and tripping, thumbs, open glove slapping, and other infinite tools at his immediate disposal. (Today's ignorant kids think the only ways to cheat are with low blows, butts and biting, thanks to Tyson, Golota and Holyfield.) When Loughran challenged Carnera for the heavyweight title in Miami, Primo's best punch of the fight was a backhand. Max Baer also used a couple of backhands to finish off Schmeling.
Ali was sticking his hand straight often to opponents face and tagged thier face with back side of it. Not very dirty but still.
Hearns, it might have been unintentional with that flicking jab of his but i see it all the same :deal
I would go for Baer, Not only Schmeling, But Carnera was a victim of the backhands by Baer also. Think one even was the cause of one of the knockdowns.
