Playing black, Gupta lost from a position of strength going wrong in a tactical middle game, and will now have to find a way back in the tournament with six rounds still remaining.
Grandmaster Maxime Vachier Lagrave of France jumped into sole lead at the expense of Daniel Gormally of England. With his third victory in as many games, Lagrave maintained a clean slate and is followed by seven players with 2.5 points apiece.
Gupta is on joint ninth spot with two points and will meet Ori Kobo in the next round. While the game between Popilski and Gupta in Durban 10 days ago had ended in a draw, the Indian had prepared well and got a good position out of his Grunfeld defense this time.
Popilski however continued with his fighting chess and posed some tactical problems and it was here that Gupta faltered. Missing out on a massive attack launched at his king, Gupta accepted a piece sacrifice from Popilski which proved disastrous. The technicalities thereafter were not a major issue for the Israeli player.
Amongst the higher seeds, Vachier played a technical masterpiece to down Gormally from a Siclian Najdorf defence game. Playing black, the Frenchman seized the initiative after the trade of queens and skilfully won a pawn to reach a winning endgame.
Important results round 3: Daniel Gormally (Eng, 2) lost to Maxime Vachier-Lagrave (Fra, 3); Elisabeth Paehtz (2.5) drew with Sergei Tiviakov (Ned, 2.5); Gil Popilski (2.5) beat Abhijeet Gupta (Ind, 2); Michael Adams (Eng, 2.5) beat Jorden Van Foreest (Ned, 1.5); Simon Williams 2457 (Eng, 1.5) lost to Gabriel Sargissian (Arm, 2.5); Nitzan Steinberg (Isr, 2) drew with David Howell (Eng, 2); Nigel Short (Eng, 2.5) beat Danny Raznikov (Isr, 1.5); Daniel Fridman (Ger, 2.5) beat Eylon Nakar (Isr, 1.5); Almira Skripchenko (Fra, 1.5) lost to Mihail Marin (Rou, 2.5); Alan Merry (Eng, 2.5) beat D Harika (Ind, 1.5).
