Many people know that Botvinnik's first major international success was a tie for first with Capablanca at the very powerful Nottingham 1936 tournament (one of Capa's last major international successes)
But the way it happened is rather interesting. Going into the final round, Botvinnik and Capa were tied for first, with Capa playing Bogolubov, and Botvinnik drawing the much easier opponent, William Winter. Capablanca built up a winning position against Bogo, but after a blunder, fell into an inferior ending and just held the draw. A win would give Botvinnik clear First.
But quite the reverse happened. Botvinnik fell into a very bad position, and should have lost, giving Capa clear first. But at the crucial moment, Winter wimped out, intimidated by the strength of his opponent, and agreed to a draw in an almost certainly winning position. The result: a tie for first.