How I botched a knight vs bishop endgame

I had an advantage, then blew it to go to a drawing endgame, but my opponent right here made a critical mistake a couple moves ago, so now I, White, have a win. Unfortunately, I missed it and made a move which loses instantly. I got a gift back later, though, and drew the game.

The correct move here is 1. h5! Both ...g5 and ...gxh5 lose. After 1. ...gxh5 2. Nf3 White puts the knight on h4 and starts pushing the f-pawn. Black will lose the h-pawns and have to give up the bishop for the f-pawn, leaving an easy win for White.