Sicilian success with a knight sacrifice

It was very satisfying to win this correspondence game, my highest rated win to date. I took a chance sacrificing a knight after my opponent appeared to castle on the 'wrong' side, and managed to make it stick by following through with checkmate. That wasn't before I had to withstand pressure against my own king and concede more material, though. The decision to sacrifice the knight meant that it was all or nothing from a very early stage.