When the horse doesn't manage to pawn.
(Excuse me for my english. I use google translator.)
Two years ago I had elo 790. Elo 1350 seemed as unattainable. Even in a dream I never thought that once I win with player elo 2160. It's my best result so far. What is wrong in my opinion he has done?
Game'm starting his mistake in 27. move. He wrote me, that such an mistake does once a year. However, that was only compensate the game.
Bigger mistake was then made mass exchange. He lost the advantage of a better player. There was no need to combine the power.
And an even bigger mistake was, that after exchanges his horse too far. Vainly chased my pawn. Finally he had to sacrifice himself.