Viswanathan Anand suffered a setback as he was beaten in the tenth game of the 12-game World Chess Championship final, where challenger Vladimir Kramnik, playing with white pieces, fought his way back into the match with a 29-move win.
The victory enabled Kramnik cut Anand's lead to 6-4.
Anand still needs only a draw in one of the two remaining games to emerge champion again.
Kramnik needs to win both the 11th and 12th games to force a tie-breaker in the title match.
The Russian stayed alive in the match as he struck back by cracking through Anand's defence in 29 moves from a Nimzo Indian defence. It was Kramnik's first win after three losses and six draws in previous nine games.
Anand, who led 6-3 after nine games, faltered as the Russian finally seemed to have found his form.
In the 10th game, which Anand needed just to draw to emerge champion, Kramnik adopted an aggressive posture in the Nimzo Indian defence from the Indian. The game went into the three knights defence, which Garry Kasparov has used effectively in the past against Anand. Anand, on that occassion, salvaged a draw, but here Kramnik went off that line and ensured a lease of life for him in a match that seemed to spell doom after three losses in four games from the third to the sixth.
Kramnik worked his way into a slight advantage midway through the game and even as Anand continued to have his chances to draw, the Russian forced his way through and took charge of the c4 square and from thereon built the pressure which forced the Indian to resign after 29 moves.
The 12-game final carries a purse of 1.5 million euros with both getting an equal amount regardless of the result.
Moves - Game 10
Kramnik v Anand
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Nf3 c5 5. g3 cxd4 6. Nxd4 O-O 7. Bg2 d5 8. cxd5 Nxd5 9. Qb3 Qa5 10. Bd2 Nc6 11. Nxc6 bxc6 12. O-O Bxc3 13. bxc3 Ba6 14. Rfd1 Qc5 15. e4 Bc4 16. Qa4 Nb6 17. Qb4 Qh5 18. Re1 c5 19. Qa5 Rfc8 20. Be3 Be2 21. Bf4 e5 22. Be3 Bg4 23. Qa6 f6 24. a4 Qf7 25. Bf1 Be6 26. Rab1 c4 27. a5 Na4 28. Rb7 Qe8 29. Qd6 1-0.