Mate with Rook and Knight

In a game of speed chess versus Juanpablogonzalez of Argentina, I mated with my rook and knight. My opponent, who played black, probably never saw the mate. Here are the moves of the game along with my commentary:

1. d4 d5
2. c4 Be6

Black makes an unusual move. More common moves are c6, e6 and dxc.

3. c5 a6
4. Nc3 h6
5. Bf4 Nc6
6. Nf3 Nf6
7. e3 Bf5

I want to prevent black from playing Nb4 on his next move because this targets c2.

8. Bd3 Bxd3
9. Qxd3 e6
10 a3 Be7
11. 0-0 0-0
12. b4 Na7

I have a space advantage.

13. h3 c6
14. Rad1 b6

The knight on a7 is ineffective.

15. e4 bxc
16. bxc Nc8

The knight is even more ineffective on c8.

17. Ne5 Qe8
18. Nf3 a5
19. exd exd
20. Rfe1 Qd7
21. Ne5 Qb7
22. Rb1 Qa6

Black wants to exchange queens, but my queen is more valuable.

23. Qg3 Bd8

Black misses my next move.

24. Bxh6 Nh5
25. Qg4 g6
26. Nxg6 Re8

This is a blunder but black cannot save the rook.

27. Rxe8+ Kh7

This is black's only legal move.

28. Rh8#

The knight on g6 and the bishop on h6 are hanging, but this does not matter. I mate the black king with a combination of my rook and knight. Black cannot protect the back rank.

I take advantage of black's cramped position, lack of control of the back rank and exposed king to force mate. Black plays a number of dubious moves such as Nc8. This move worsens his position and gives me a space advantage. The black rooks play no active role in the game.