World Championship 1987: Kasparov – Karpov

Trailing 12–11 with a single game to play, Kasparov had to win the twenty-fourth game to tie the match and keep his title. He did — grinding Karpov down to a resignation on move 64 — and retained the crown on a 12–12 tie.

◇The first match off Soviet soil

The fourth Kasparov–Karpov contest was the first played entirely outside the Soviet Union, in Seville. It swung back and forth for weeks; then, in the twenty-third game, Kasparov miscalculated a combination he later called the "worst hallucination of my career," handing Karpov a 12–11 lead with only one game left.

The champion now had to win to survive.

◇Everest

Needing a full point on demand, Kasparov reached for the English Opening and slowly squeezed. Cracking under time pressure and a second-session error, Karpov was ground down and resigned on move 64. The match finished 12–12 (+4−4=16), and Kasparov kept his title.

It remains, in Kasparov's own telling, the single 'Mount Everest' of his career.

“I can look back at my chess career and pick out more than a few crisis points, but only one Mount Everest.”