1. James “Buster” Douglas KO 10 Mike Tyson. February 1990, Tokyo Japan.
This one absolutely nobody saw coming. Likely to never be topped as far as the biggest heavyweight – or indeed, boxing upsets go, Douglas’ win stunned the entire world. Tyson was seen by practically everyone as invincible, while Douglas was seen as an overweight, often lazy fighter who had lost his biggest fight to date; a title fight with Tony Tucker. A quick Tyson win was predicted, instead Douglas smashed the defending champion to sensational in what was a great fight.
Fury’s upset win was big, but not as big as this.