This game shows how one natural move can turn a good game into a lost position.
1.e4
c5
2.Nf3
d6
3.Nc3
Nf6
4.g3
g6
5.Bg2
Bg7
6.0-0
Nc6
7.d3
Bg4
8.h3
Bd7
9.a4
0-0
10.Ne2
a6
11.c3
b5
12.axb5
axb5
13.Be3
Qc8
14.Rxa8
Qxa8
15.e5
Nd5
16.exd6
Nxe3
17.fxe3
exd6
18.Nf4
Qa2
19.Rf2
Ra8
Here the position is roughly equal. [19...b4!?
20.Ng5
Ne7
is an alternative not pinning the rook on the diagonal]
20.Ng5
Looks primative but it does have a point.
20...h6??
A blunder missing whites next move which wins the queen or mates black in two moves. [20...Qa1
is about level after an exchange of queens. 21.Qxa1
Rxa1+
22.Kh2
Ne5
(22...Nd8
23.Ne4
Ra6
24.Nd5
Be6
25.Nef6+
Bxf6
26.Nxf6+
Kg7
) 23.Ne4
Re1
]
21.Bd5
Qa1
22.Bxf7+
White mates next move with Nxg6. 1-0