With his first win in four games, Anand jumped to joint third spot on three points. This victory also served as a morale booster after an indifferent start that involved two losses and a draw in the first three rounds.
All three games in the highest category event ended decisively.
World champion Magnus Carlsen avenged his blitz loss against Fabiano Caruana of Italy with a comprehensive win, while Levon Aronian of Armenia played like a machine to beat Hikaru Nakamura of United States.
Carlsen scored his third victory in four games to take his personal tally to seven points in all under the unique scoring system that gives two points for a win and one for a draw in the Classical games.
The recently crowned world champion is making most of the opportunities here and was seen at his technical best against Caruana.
Aronian remains on the heels of Carlsen a full point behind and he enjoys a huge three points lead over his nearest rivals Anand, Caruana and Nakamura -- who all are on three points.
Gelfand is on the last spot with two points in his kitty.
One game in Classical and five rounds in rapid still remain in the tournament.
Anand has his task cut out against Gelfand and he did not disappoint. The Indian used the Slav defense yet again and when Gelfand went for opposite side castling the complexities were aplenty. The trading of pieces at regular intervals let the position be close to equal but Gelfand erred in the ensuing queen and rook endgame.
Anand pocketed one pawn and when he was ready to gobble the second, Gelfand called it a day. The game lasted 36 moves.
Carlsen employed the Anti-Berlin variation as white and showed a completely new approach in the middle game. Going for early exchanges that led to an opposite colour Bishops middle game, the Norwegian spotted a fine exchange sacrifice that left Caruana baffled. What transpired was a brilliant execution of technique thereafter as Carlsen combined his Queen Bishop and passed pawn to force matters in 47 moves.
Aronian faced the King's Indian defense by Nakamura and relished a queen side pawn weakness in the early middle game. The pawn was taken with perfect display and Nakamura, who misplayed a won position against Carlsen in the previous round, did not get any chance to come back in the game.
In the final Classical game now, Anand will meet Carlsen and Aronian is set to play against Caruana. The battle will then move to the rapid format under which normal point scoring system will be used to determine the winner.
Results Round 4: Boris Gelfand (Isr, 2) lost to V Anand (Ind, 3); Levon Aronian (arm, 6) beat Hikaru Nakamura (Usa, 3); Magnus Carlsen (Nor, 7) beat Fabiano Caruana (Ita, 3).
Image: Viswanathan Anand
Photograph: Patrik Stollarz/Getty Images
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