Muhammad Ali once named the heavyweight he feels would have caused him the most problems inside a boxing ring.

Paul and Ali both suffered broken jaws in the boxing ring. A wicked right hand from Joshua broke Paul’s jaw in two places Friday night based on an X-ray that Paul posted online. The punch also knocked out Paul in the sixth round of their heavyweight fight. In 1973, Ken Norton broke Ali’s jaw.

He was fast of fist and foot -- lip, too -- a heavyweight champion who promised to shock the world and did. He floated. He stung. Mostly, he thrilled, even after the punches had taken their toll and his voice barely rose above a whisper. He was "The Greatest.