20 Qb3-c2! White threatens 21 Nd5-e7+, 22 Qc2xh7+!, 23 Re3-h3# Leko vs Gelfand, 2009  (C42) Petrov Defense, 43 moves, 1-0 29 Qh6xg5?? allows mate after 29 ... Nf4-e2+ and 30 .. Qd6xh2+! Kramnik vs Anand, 2007  (D43) Queen's Gambit Declined Semi-Slav, 41 moves, 1/2-1/2