Pendyala Harikrishna toppled tournament leader Viktor Korchnoi of Switzerland [Images] to take sole lead after the seventh round in the Marx Gyorgy Memorial International chess tournament in Paks, Hungary.

The defending champion, who started off with a defeat and three draws in the Category-14 tournament, scored his third victory on the trot and, with 4.5 points, has emerged as the favourite for his second successive title.

Korchnoi and Csaba Balogh of Hungary share second place on four points each. Peter Acs of Hungary is fourth in the standings on 3.5 points, a half point ahead of compatriot Ferenc Berkes while Chinese Hou Yifan remains at the bottom of the table on two points. Besides Harikrishna, Balogh was the other winner of the day, defeating Yifan.

The former world junior champion's victory against Korchnoi was easy. At 77, the legendry Swiss GM is clearly past his prime but the agility with which he carries out his moves on board is still a spectator's delight.

Playing white, Harikrishna faced the Queen's Gambit accepted and got a slight advantage typical of the opening.

Korchnoi, however, had his pieces controlling key squares but a rook lift from the queen side did the trick for Harikrishna.

Just while the attack was building, Korchnoi crumbled and found himself in an Opposite colour Bishops endgame with a pawn less. Harikrishna converted the material advantage into a full point after 43 moves.

"It's nice to be on the winning side again. I think he misjudged the potential in my position. It was a new position for me but after I found this king side attack plan I thought I was already better," Harikrishna said.

In the last three rounds, Harirkishna has two black games scheduled against Berkes and Balogh while his remaining white will be against Yifan. To get some important rating points, he needs to score minimum 6.5 from the tournament while anything over and above this figure will add to his present rating.

Csaba Balogh caught Yifan unawares in the middle game arising out of a Sicilian Najdorf. Playing white, Balogh got a slightly better position out of the opening and later launched his attack through the central files against a vulnerable black king. Yifan's counter play bid never materialised and the game was over on the 40th move.

Peter Acs played the Hungarian system against the Grunfeld defense of Berkes. The complexities ensued early in this keenly contested game with Berkes promoting one of his pawn to a new queen as early as on 30th move itself.

Acs, however, had things under control as he recaptured the newly promoted queen and after further action that lasted another couple of hours, the game was finally drawn.

Meanwhile, in the Paks Cup GM tournament Indian women champion Tania Sachdev was held to a disappointing draw by lowest ranked Pataki Gyozo of Hungary in the eighth round and will now need a win against GM Vladislav Nevednichy in the final round to get her second IM norm.

GM Attlia Groszpeter of Hungary regained sole lead in the tournament, defeating Krisztian Szabo.

Tania is placed seventh with three points from eight games.

Results round 7 (Marx Gyorgy Memorial):

P Harikrishna (Ind, 4.5) beat Viktor Korchnoi (Sui, 4); Csaba Balogh (Hun, 4) beat Hou Yifan (Chn, 2); Peter Acs (Hun, 3.5) drew with Ferenc Berkes (Hun, 3) Paks Cup round 8: Pataki Gyozo (Hun, 2.5) drew with Tania Sachdev (Ind, 3); Vladislav Nevednichy (Rou, 5.5) beat David Smerdon (Aus, 2.5); Attilia Grszpter (Hun, 6) beat Krisztian Szab (Hun, 5); Papp Gabor (Hun, 5.5) drew with Yu Shaoteng (Chn, 4); Mihai Grunberg (Hun, 2.5) lost to Andras Flumbort (Hun, 3.5).

The moves: P Harikrishna v/s Viktor Korchnoi

1. d4 d5 2. c4 dxc4 3. Nf3 e6 4. e3 c5 5. Bxc4 Nf6 6. O-O a6 7. Bd3 Nc6 8. dxc5 Bxc5 9. a3 Bd6 10. h3 Ne5 11. Nxe5 Bxe5 12. Qe2 O-O 13. Nd2 b5 14. Nf3 Bd6 15. a4 bxa4 16. Rxa4 Bb7 17. e4 Nd7 18. Be3 a5 19. Rd1 Qe7 20. Rd4 Rfd8 21. e5 Nxe5 22. Bxh7+ Kxh7 23. Nxe5 Kg8 24. Qh5 Bxe5 25. Qxe5 Rxd4 26. Rxd4 Qf6 27. Qc7 Bd5 28. Rf4 Qg6 29. Rg4 Qb1+ 30. Kh2 Qxb2 31. Bd4 Qb8 32. Rxg7+ Kf8 33. Rxf7+ Ke8 34. h4 Qxc7+ 35. Rxc7 Rb8 36. Bc3 a4 37. h5 Rb7 38. Rxb7 Bxb7 39. Bb2 Ke7 40. g4 Kd6 41. f4 Be4 42. Kg3 Ke7 43. g5 black resigned.

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