World champion Viswanathan Anand suffered a shock defeat at the hands of Peter Leko of Hungary in the rapid game of the fourth round of the Amber Blindfold and Rapid chess tournament here.
The loss proved quite costly for Anand as he lost his lead position in both 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 5 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 3 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 and Ivanchuk, Carlsen, Topalov and Vladimir Kramnik of Russia 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.