[I]n many of [Gioachino Greco's] games the attack is founded on bad play, the party who wins making the first bad move, which succeeds only because his adversary plays worse.Observing Greco's games, William Lewis described a pattern that continues to hold true in many games between amateurs. My online game this morning illustrates the point. Both players blundered bad enough to alter the evaluation dramatically. The player who blundered first won the game.
William Lewis, Gioachino Greco on the Game of Chess (1819), vi.
With White, I adopted a rare and suspect line against the Berlin Defense to the Spanish. This line gave Black easy equality, but the equilibrium was upset when I blundered. Black squandered his advantage a few moves later. The time control was game 15.
Stripes,J (1679) -- Internet Opponent (1627) [C67]
1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.0–0 Nxe4 5.Qe2
5.d4 is the normal move.
5.Re1 is playable.
5...Nd6 6.Bxc6 dxc6 7.Re1?!
7.Qxe5+ Qe7 8.Qa5 Qd8 (8...Be6 9.d3 Nf5 10.Bf4 0–0–0 11.Qxa7 Qb4 12.Ne5 1–0 Winawer,S -- Schmid,C Berlin 1881) 9.Qc3 Qf6 10.Re1+ Be7 11.Qxf6 gxf6 12.d3 Be6 13.Nbd2 Nf5 14.b3 h5 15.Bb2 h4 16.Ng5 Kd7 17.Nxe6 fxe6 18.Re4 Rae8 19.Rae1 Bd8 20.Nf3 c5 21.h3 Rh7 22.d4 cxd4 23.Nxd4 Ng7 24.Nf3 Nf5 25.Nd4 Ng7 26.Nf3 Nf5 27.Rb4 b6 28.Ra4 a5 29.Rd1+ Kc6 30.Nd4+ Nxd4 31.Raxd4 Rhh8 32.Rc4+ Kb7 33.Rd7 e5 34.a4 Re6 35.Ba3 Rc6 36.Rxc6 Kxc6 37.Rf7 Kd5 38.Kf1 Ke6 39.Rf8 Rxf8 40.Bxf8 f5 41.Ke2 Kd5 42.Bh6 Be7 43.Bc1 Bf6 44.Kf3 Ke6 45.Bd2 Be7 46.Ke2 Kd5 47.Bc1 Bd8 48.f3 Be7 49.Be3 f4 50.Bc1 c5 51.Kd3 Bd8 52.Bd2 Be7 53.Be1 Bd8 54.c3 Be7 55.c4+ Ke6 56.Ke4 Bd8 57.Bc3 ½–½ Andreikin,D (2705) -- Ni Hua (2670) Saratov 2011
7...Be7 8.Nxe5 Be6 9.d4 0–0
White to move
10.Nxf7 Bxf7 11.Qxe7=
10...Nf5 11.Nf3 Nxd4 12.Nxd4 Qxd4-/+ 13.Nd2 Rad8?!
13...Rfe8 seems more in tune with the position.
Black to move
Black trades a substantial advantage for a position that may be close to losing.
14...Qg4 maintains the advantage.
15.Qxc4+/- Bxc4 16.Rxe7 Rfe8 17.Rxe8+ Rxe8 18.Bf4 Be2?
Black to move
19...f6 20.Nd4 Bh5 21.Rxe8+ Bxe8 22.Bxc7 Kf7 23.Bb8 a6 24.Nf5 Bd7 25.Nd6+ 1–0