Smothered (help) mate

[Event "Challenge"]
[Site "http://www.redhotpawn.com"]
[Date "2011.12.19"]
[White "watchyourbackrank"]
[Black "anonymous"]
[Result "1-0"]
[ECO "B09"]
[WhiteElo "1973"]
[BlackElo "na"]
[PlyCount "35"]

1. d4 g6 2. e4 Bg7 3. Nc3 d6 4. f4 Nf6 5. Nf3 O-O 6. Bd3 Nc6 7. e5 {one of the problems for black when he plays an early Nf6} dxe5 8. fxe5 Nh5 9. Be3 Bg4 10.Bc4 {usually not a good idea to move a piece twice in the opening. Here it seems to make sense though. The bishop is now much more agressive on c4} e6 {shutting down my bishops new diagonal. The problem for black is that it also commits his bishop to exchange on f3 making his knight on h5 vulnerable to a g4 attack} 11. O-O a6 {intending b5 next} 12. a3 {making space for my bishop} Qd7 13. Ne4 {centralizing my knight giving access to squares like c5 and f6} Rad8 {adding pressure on d4} 14. c3 b5 15. Ba2 {I decided to keep my bishop on the long diagonal hoping for future tricks on e6 or g6} Bxf3 {this is a mistake} 16. Qxf3 {black knight on h5 is in trouble} Bh8 {planning to retreat the knight to g7} 17. g4 Ng7 {according to plan. Unfortunately it was a bad plan because of mate next move} 18. Nf6 {smothered mate with friendly assistance from black which is why it should probably be categorized as a help mate. No matter what it was another victim of a backrank mate lol}