I look at it another way. What other guys did Rahman and McCall one punch KO? And, of f course, someone is gonna tag you. The ones with great chins take the shots, no matter the opponent. Others, like Lewis, do not. Prime Holmes and Ali faced a slew of big punchers and did not get KOd. Ali did get caught with Fraziers best left hook and went down, but his awesome recuperative powers allowed him to quickly recover and fight on. Holmes was leveled by Shavers, who certainly had far greater one punch power than Rahman or McCall. He got up and won the fight. They did suffer KOs when way past their best, against Holmes and Tyson, respectively. But, their losses at that late juncture of their careers were largely expected. Lewis, on the other hand, was still in otherwise prime form, was done after going down against Rahman and McCall. Not only did he show a weak chin, but, even more importantly, weak recuperative powers.