If boxing worked like math, Muhammad Ali would have come out on the losing end of the equation. Per NPR, Foreman explained had beaten Ali’s bitter rival, Joe Frazier, and Frazier had beaten Ali. Foreman had also defeated Ken Norton, who defeated Ali. By the transitive property of beatings, Foreman should have clobbered Ali and retained his championship. But Foreman made a grave miscalculation: he underestimated Ali

“I figured I’d knock him out in three rounds,” Foreman admitted. But when Ali had a winning strategy: the rope-a-dope. Decades later Foreman would say, “It was the performance of a lifetime … I wish I had been able to tell him that right after it happened.” The former world champion wasn’t the only person who was stunned that night. Foreman told ABC that years later he received a phone call from Ali: “I do not know how he got my number. He called and complimented me for about 20 minutes.”

Ali had so much respect for Foreman as a knockout artist that he asked him to make Ken Norton his next masterpiece. “I can’t beat him. George, you can. He’s afraid of you,” Ali reportedly said. With that, he and Foreman became “the best of friends.” Their children became friends as well. When asked why he befriended the person responsible for what Foreman called “the most embarrassing moment” of his life,” Foreman replied, “If you beat me up like he did, I’d be your friend too.”