February 15, 1978: In only his eighth professional bout Leon Spinks defeated undisputed heavyweight champion Muhammad Ali in one of the biggest upsets in boxing history.

Only seven months later he was stripped of the WBC title for fighting Ali in an unapproved rematch instead of No. 1 challenger Ken Norton. Instead of fighting Norton, Spinks lost by unanimous decision after 15 rounds. His career would fall apart after that loss.

But on this day, 37 years ago at the Hilton Hotel in Las Vegas, Spinks was king of the ring. By winning in his eighth professional fight, Spinks gained the world title faster than any boxer in history. The aging Ali expected an easy fight against the 10-1 underdog Spinks, but he was outboxed. Ali left the fight with a puffy face.

Ali knew he messed up. He had only sparred two dozen rounds in preparation for the fight and had been clearly out of shape.

“I let him rob my house while I was out to lunch,” Ali said of the loss.

Watch the whole fight right here:

Here’s to you Leon Spinks, and your 15 rounds of fame.

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