Unfortunately I have since had to shut down the computer and did not save the game. I didn't think you needed me to keep it up anymore, so I don't have the exact moves before me. However, you could be right that the position was unfavorable by move 21. Nevertheless, when an opponent is pressing against you, you can sometimes buy yourself time by checking him. This may have been possible in order to gain a more advantageous position.

Your strategy was sound, as a single pawn advantage is a guaranteed victory if held onto long enough. But I turned the tables when I captured your knight, so even if I had not used that queen/rook combo, I still had the material advantage by that point. Remember, it wasn't just any pawn I gave up. It was a pawn right next to my king, which could have afforded opportunities for exploitation early in the game. That's why I quickly castled queen-side. And later, when I'd opened up the b file, you could have tried to exploit that for an attack. My pawn structure was very weak by that point.

Again, I hope this doesn't sound condescending. Just offering some friendly advice. I'm always open to any insights you might have as well. :)