Former world champion Viswanathan Anand played out another draw with Anish Giri of Holland and remained joint second after the sixth round of the Sinquefield Cup, a part of the Grand Chess Tour.
The Indian ace had to ward off heavy pressure from the highest-ranked Dutchman and Anish Giri will be haunted by his 40th move for some time as he blundered on it before the first time control.
Wesley So of United States emerged as the new sole leader after disposing off overnight leader Veselin Topalov of Bulgaria in fine fashion. Wesley came up with an inspired performance with his white pieces and roughed up Topalov onboth flanks before his passed pawn took the centre-stage.
The Filipino, who recently changed his federation to play for US, took his tally to four points out of a possible six and now enjoys the top position. Anand and Topalov are not far behind the leader on 3.5 points apiece.
With just three rounds remaining, the event is still wide open as Levon Aronian of Armenia, Maxime Vachier-Lagrave of France, Hikaru Nakamura of United States and Ding Liren of China share the fourth spot on three points each. Anish Girion 2.5 is on ninth spot, a point ahead of Russian Peter Svidler.
It was thus far the most result-oriented day in the Sinquefield cup with as many as three decisive games out of five. Besides Wesley, Ding Liren joined the party defeating an out-of-sorts Svidler while Vachier-Lagrave scored his first victory in the tournament at the expense of Aronian.
The other two games of the day between Nakamura and Caruana was drawn with the former unable to win with his two rooks against Caruana's queen.
Giri and Anand battled it out in the English opening where the former played white. It was a pretty easy game for along time after Anand equalised but a small lapse in concentration allowed Giri to liven things up on the 26th move.
"This was a real shock because you think you are playinga normal game, and then you realise you are losing control. So I was a bit shaken by this," he said.
Shaken he was as Anand made some further inaccuracies and was in a difficult situation when Giri left with just four seconds allowed Anand to escape with a draw by returning the favour on the 40th move.
Results round 6: Anish Giri (Ned, 2.5) drew with V Anand(3.5); Wesley So (Usa, 4) beat Veselin Topalov (Bul, 3.5); Maxime Vachier-Lagrave (Fra, 3) beat Levon Aronian (Arm, 3); Hikaru Nakamura (Usa, 3) drew with Fabiano Caruana (Usa, 3); Ding Liren (Chn, 3) beat Peter Svidler (Rus, 1.5).