In heavyweight history there was no bigger upset that this one. James "Buster" Douglas entered the ring a 42-1 underdog for the fight in Tokyo in 1990. Tyson was the undisputed heavyweight champion, an undefeated knockout machine who beat most guys before they stepped into the ring.
Douglas was a journeyman with a 29-4 record and had only fought for a title once, a knockout loss to Tony Tucker. To compound matters, his mother passed away during his training for the fight with Tyson, and he himself entered the ring with the flu.
Nobody, but gamblers looking to make a historic payday, gave Douglas any sort of chance to beat "Iron" Mike. And the story, as so many in Tyson's career, has many twists and turns.
Douglas refused to be bullied by Tyson and wasn't afraid to let his hands go. Every time Tyson attempted to get on the inside he would pay for it. It was the first time another fighter had both the skill and the guts to stand up to the most feared man in the game.
Douglas was winning the fight when in the eighth round he was dropped by a vicious Tyson uppercut. He rose by the count of nine, a fact that remains highly disputed to this day. Many have argued, including Tyson promoter Don King, that the count went well over nine seconds and the fight should have ended.
But it didn't and Douglas quickly turned the tide back to his favor, punishing an extremely aggressive Tyson, who was sensing his titles slipping away, in the ninth round. By the end of the round it appeared Tyson, not Douglas, was ready to go.
It was in the 10th round that a badly beaten up Tyson finally succumbed to the pressure. Douglas landed a huge uppercut that staggered the champ, following by several punches while Tyson was reeling that deposited him on the mat. He would not beat the count, making this one of the, if not the biggest upsets in boxing history.