Even weaker moves sometimes win

My opponent yesterday evening tried a Teichmann Exchange against me - and guess what - I had covered the line already in an earlier post. And guess another thing - I forgot about it ! But luckily I was able to pull off a nice attack, resulting in a nice win.

Guido De Bouver - Velibor Novakovic
1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bxf3 7.Qxf3 c6 8.g4 e6 9.g5 Nd5 10.Bd3 Be7 11.h4 Nd7 (diagram)
I covered this position in an earleir post "Black's difficult Teichmann Exchange defense" in May 2011. In there, I suggested 12.Nxd5, leading to an equal game.

12.Bd2 N7b6 13.000 Nxc3 14.Bxc3 Nd5 (diagram)

14...Qd5 would have been better, as the gambitplayer is not in a position to exchange queens.

15.Rdf1 00
Black is forced to castle into it

16.Qe4 (diagram)

An important move that appears frequently in white's attack in the Teichmann Exchange. It forces black to create a weakness.

16...g6 17.Bd2 Nb4 18.Bc4 Nd5 19.Kb1
A preparation move, so that the balck queen will not be able to check on g5.

19...b5 20.h5 (diagram)

Not so good. 20.Bd3 would have given me a decent advantage. But my move atatcks the black king at the expense of a piece - most chess players start makinmg mistakes when their king is attacked this way.

20....Bxg5 ?? 21.hxg6 1-0

So we see that Blackmar Diemer gambiteers dont necessarily have to play the best moves to create dispair in the defending ranks.