Viswanathan Anand played his third draws in six games to stay in the tied second place with Peter Svidler, even as Veselin Topalov continued his brilliant run with a fifth win in six games at the World Chess Championships in San Luis, Argentina.
Barring Topalov's win over Judit Polgar in seven hours and 67 moves from a Ruy Lopez Berlin Wall, the other three games played on the day were hard-fought exciting draws at the Hotel Potrero de los Funes Complex, in the province of San Luis.
Anand and Svidler now have 3.5 points each, while Bulgarian Topalov extended his lead to full two points after six rounds of the tournament.
Anand and Svidler fought for 39 moves, with the Indian former world champion pressing, but to no avail. Kasimdzhanov versus Leko was a complex game, but ended in a 43 move draw. Adams and Morozevich split the point after six hours and 76 moves.
Anand was on the white side of a Marshall attach in Ruy Lopez. Anand enjoyed an extra pawn alongside his bishop as compensation for a rook. Anand took a couple of queenside pawns but at the cost of losing co-ordination.
Svidler got several opportunities to check the white king, but Anand had no problems dealing with them. In the end, the duo decided to draw after 39 moves just before the first time control.
Anand plays Alexander Morozevich in his next match.
Polgar, who has tremendous stamina and lasts long games, stretched Topalov once again, but the Bulgarian who is having a great year kept pressing for a win. After seven hours with white pieces, Topalov's perseverance paid off. The win gave him a two-point lead over his nearest rivals Anand and Svidler.
Rustam Kasimdzhanov, who beat Anand in an earlier round, drew with Peter Leko in a Sicilian Sveshnikov game. The game between Michael Adams and Alexander Morozevich also ended in a draw.
Topalov now has five white and three black games in the remaining eight games and is a heavy favourite to win.
Results of Round 6: Anand drew with Svidler; Kasimdzhanov drew with Leko; Polgar lost to Topalov; Adams drew with Morozevich
Pairings for Round 7: Morozevich v Anand; Svidler v Polgar; Topalov v Kasimdzhanov
Standings after Round 6:
1. Topalov 5.5
2. Anand and Svidler 3.5
4. Kasimdzhanov 3.0
5. Leko 2.5
6. Adams, Polgar and Morozevich 2.0
Anand vs Svidler (round 6):
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3 d5 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5 c6 12. d4 Bd6 13. Re1 Qh4 14. g3 Qh3 15. Re4 g5 16. Qf1 Qxf1+ 17. Kxf1 Bf5 18. f3 h6 19. Nd2 Bxe4 20. fxe4 Nc7 21. Kg2 c5 22. e5 Be7 23. Ne4 cxd4 24. cxd4 a5 25. Be3 a4 26. Bd1 Nd5 27. Bf2 Rac8 28. Rb1 f6 29. exf6 Bxf6 30. Nd6 Rc6 31. Nxb5 Rb6 32. Bxa4 Rfb8 33. Na3 Rxb2 34. Rxb2 Rxb2 35. Nc4 Rxa2 36. Bb3 Rxf2+ 37. Kxf2 Bxd4+ 38. Ne3 Bxe3+ 39. Kf3 draw agreed