The answer's simple: 28. Qxa4? Bxg3! 29. fxg3 Qxe3+ with great Carlsen vs Nakamura, 2010  (A10) English, 59 moves, 1-0 27 Qd1-d4! overloads Black g7-pawn with Nf5xh6 and Qd4xNf6 Carlsen vs Ivanchuk, 2011  (D38) Queen's Gambit Declined, Ragozin Variation, 72 moves, 1-0 47 ... Bc3xe5! White e4-queen must defend against ... Qb2xBc2 Shirov vs Carlsen, 2011  (C65) Ruy Lopez, Berlin Defense, 60 moves, 0-1 37 Nd4-f5! e6-pawn protects d5-bishop from unmasked d1-rook Carlsen vs Svidler, 2011  (D86) Grunfeld, Exchange, 53 moves, 1/2-1/2 36 .. Rb4xb3! White c2-queen cannot protect b3-pawn,d2-check sq Carlsen vs Nepomniachtchi, 2011  (B52) Sicilian, Canal-Sokolsky (Rossolimo) Attack, 40 moves, 1/2-1/2 35 c2-c4! J Polgar vs F Corrales Jimenez, 2011  (B43) Sicilian, Kan, 5.Nc3, 52 moves, 1-0 33.Bf5!+- would have won the game on the spot J Polgar vs Vachier-Lagrave, 2011  (B90) Sicilian, Najdorf, 44 moves, 1/2-1/2 38 Rd1-d5!! Black b6-knight cannot protect a4-queen, d5-square Mamedyarov vs Ivanchuk, 2007  (D43) Queen's Gambit Declined Semi-Slav, 39 moves, 1-0 25 ... Bf5-d3! White c2-pawn must defend against ... Qb4xNb3 Radjabov vs Kamsky, 2011  (C45) Scotch Game, 39 moves, 0-1 46 ... f5-f4! 0-1 White f2-queen must protect b2-rook from a1-Q G Koushik vs R Hovhannisyan, 2011  (D43) Queen's Gambit Declined Semi-Slav, 46 moves, 0-1 21 ... Ne4-f2! e2-queen must protect d3-bishop from f5-bishop Eljanov vs V Malakhov, 2009  (D15) Queen's Gambit Declined Slav, 31 moves, 0-1 59 ... h6-h5! J Randviir vs Keres, 1947  (C45) Scotch Game, 63 moves, 0-1 21 ... Re8-e3! White d3-queen protects c2-rook from a2-queen Szabo vs Fischer, 1960  (E70) King's Indian, 24 moves, 0-1 18 Nd2-c4? threat of ... Qb5xNa4, ...Be6xNc4 overload b3-pawn M Ragger vs Le Quang Liem, 2010  (A35) English, Symmetrical, 33 moves, 0-1 N Firman vs McShane, 2012  (C65) Ruy Lopez, Berlin Defense, 60 moves, 0-1 28 Nb3-d4! Aronian vs H Stevic, 2010  (D20) Queen's Gambit Accepted, 33 moves, 1-0 15 ... c7-c5! b4-pawn must meet threat to capture of .. Qd8xNa5 Hracek vs Kramnik, 2002  (C65) Ruy Lopez, Berlin Defense, 23 moves, 0-1 18 ... c7-c5! b4-pawn must meet threat to capture of .. Qd8xNa5 N Grandelius vs A Ipatov, 2012  (E10) Queen's Pawn Game, 42 moves, 0-1 18 games