World champion Viswanathan Anand [Images] suffered a shock defeat at the hands of Peter Leko of Hungary in the rapid game in the fourth round of the Amber Blindfold and Rapid chess tournament in Nice, France [Images].

The defeat proved quite costly for the Indian ace, as he lost his lead in the rapid section and combined standings.

As things stand, Levon Aronian of Armenia, Vassily Ivanchuk of Ukraine and former World champion Veselin Topalov of Bulgaria share the lead with five points each in the combined standings and Anand is now sole fourth on 4 points.

In the rapid section, Aronian overtook Anand after beating Magnus Carlsen of Norway and is now sole first on three points.

Anand shares the joint second spot in this section on 2.5 points along with Topalov, Leko, and Ivanchuk.

It's a four-way lead in the blindfold. Ivanchuk, Carlsen, Topalov and Vladimir Kramnik of Russia [Images] are at the helm on 2.5 points each. With 50 per cent score here, Anand is joint-fifth on 2 points.

Things did not go as planned for Anand in the rapid game. Playing the black side of a Sicilian defense, Anand was under pressure when Leko went for an ultra sharp variation and won in just 28 moves.

Earlier, the blindfold game between the two featured a Caro Kann defense, where Anand played white. Leko was apparently satisfied with his result from the opening that gave him a reasonable position and Anand decided to repeat moves to split the point.

Ivanchuk celebrated his 39th birthday in style. The Ukrainian beat compatriot Sergey Karjakin in the rapid game and joined the leading group after drawing the blindfold played earlier in the day.

Boris Gelfand of Israeli lost on time in the blindfold game against Loek Van Wely. It was the first time that any player lost his game this way and Gelfand complained of a problem in the software.

According to the version of the Israeli, he was trying to make a move in the blindfold game when the move he intended to play was termed as illegal.

While he tried to think of another move, his time ran out. Later the arbiters found everything in order and Van Wely was given the point.

The blindfold games are played on a computer screen here with only the last played move visible to the player whose turn it is to move.

In another interesting battle of the day, Topalov defeated Shakhriyar Mamedyarov of Azerbaijan. The Bulgarian won the blindfold game with black pieces and drew the rapid to win by a 1.5-0.5 score.

Results round 4:

Blindfold: Boris Gelfand (Isr) lost to Loek Van Wely (Ned); Sergey Karjakin (Ukr) drew with Vassily Ivanchuk (Ukr); Levon Aronian (Arm) drew with Magnus Carlsen (Nor); Vladimir Kramnik (Ukr) beat Alexander Morozevich (Rus); Viswanathan Anand (Ind) drew with Peter Leko (Hun); Shakhriyar Mamedyarov (Aze) lost to Veselin Topalov (Bul).

Rapid: Van Wely drew with Gelfand; Ivanchuk beat Karjakin; Carlsen lost to Aronian; Morozevich drew with Kramnik; Leko beat Anand; Topalov drew with Mamedyarov.

Standings:

Blindfold: 1-4. Ivanchuk, Carlsen, Kramnik, Topalov 2.5 each; 5-9. Morozevich, Anand, Aronian, Karjakin, Van Wely 2 each; 10-11. Mamedyarov, Leko 1.5 each; 12. Gelfand 0.5.

Rapid: 1. Aronian 3; 2-5. Anand, Leko, Topalov, Ivanchuk 2.5 each; 6-7. Gelfand, Mamedyarov 2 each; 8-11. Van Wely, Kramnik, Carlsen, Karjakin 1.5 each; 12. Morozevich 1.

Combined: 1-3. Topalov, Aronian, Ivanchuk 5 each; 4. Anand 4.5; 5-7. Leko, Carlsen, Kramnik4each;8-10.VanWely,Mamedyarov, Karjakin 3.5 each; 11-12. Gelfand, Morozevich 3 each.

The moves:

Blindfold: V Anand vs Peter Leko

1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7 8. h5 Bh7 9. Bd3 Bxd3 10. Qxd3 e6 11. Bd2 Ngf6 12. O-O-O Be7 13. Ne4 Nxe4 14. Qxe4 Nf6 15. Qe2 Qd5 16. c4 Qe4 17. Qxe4 Nxe4 18. Be3 f5 19. Kc2 f4 20. Kd3 fxe3 21. Kxe4 exf2 22. Rdf1 Rf8 23. Rxf2 Bd6 24. Re2 Rf4+ 25. Kd3 Kd7 26. Nh4 Rd8 27. Ng6 Rg4 28. Rh4 Rxh4 29. Nxh4 Rf8 30. Ng6 Rf5 31. g4 Rf3+ 32. Re3 Rf2 33. Re2 Rf3+ game drawn.

Rapid: Peter Leko vs V Anand:

 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e6 7. g4 e5 8. Nf5 g6 9. g5 gxf5 10. exf5 d5 11. Qf3 d4 12. O-O-O Nbd7 13. Bc4 Qc7 14. Bxd4 exd4 15. Rhe1+ Kd8 16. Rxd4 Bc5 17. Rdd1 Re8 18. gxf6 Rxe1 19. Rxe1 Nxf6 20. Rd1+ Bd7 21. Bxf7 Qxh2 22. Nd5 Rc8 23. Be6 Bxf2 24. c3 Rc7 25. Nxf6 Qh6+ 26. Kb1 Qxf6 27. Qxf2 Ke8 28. Qg3 black resigned.

• Complete chess coverage