Hennigan-Kosten

Black should play 34...Bxg3! 35 fxg3 Qxg3+ 36 Bg2 Be4 37 Qb8+ (or 37 Ne7+ Kh7 38 Qb2 c3) 37...Qxb8 38 Nxb8 Bxg2, with a winning position, as after 39 Kxg2 c3 the pawn promotes. Instead there came
34...Qd7? 35 Bxc4 Bxc4 36 Qxc4 Qxh3? 37 Nxa7 Bxg3 38 Qc8+! Qxc8 39 Nxc8 Bb8 40 Ne7+ Kf8 41 Nc6 1-0