After beating erstwhile leader Wesley So of United States in the previous round, Anand's streak was halted yet again as the Indian ace faced a risk-free approach from Mamedov out of a Caro Kann defence.
The draws were the order of the day as only Fabiano Caruana of Italy could score a victory over off-form Vladimir Kramnik of Russia.
World champion Magnus Carlsen was held to a draw by Anish Giri of Holland in the key encounter of the day while Wesley So signed peace with Shakhriyayr Mamedyarov of Azerbaijan.
The lead positions remained unchanged thus, and Carlsen remained at the top of the tables with 4.5 points out of a possible six.
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Wesely So remained on the heels of the leader a half point behind and Anand's third place remained intact as the Indian inched himself up to 3.5 points after his fifth draw in sixth game.
Mamedyarov shares the fifth spot with Caruana now as the latter came back to an even score with his first victory in the tournament.
For Anand a victory might have helped but the approach by Mamedov was quite solid. The Azerbaijani, who is gaining respect with every passing round facing much higher opposition played it too safe against Anand in the Caro Kann.
The legendary Indian GM retained a solid position and it was still middle game on board when both players decided to repeat. The game was over in just 29 moves.
Giri has never lost to Carlsen in a Classic game and he kept that record intact with his white pieces.
Results round 6: Rauf Mamedov (Aze, 2.5) drew with V Anand (Ind, 3.5); Anish Giri (Ned, 2.5) drew with Magnus Carlsen (Nor, 4.5); Wesley So (USA, 4) drew with Shakhriyar Mamedyarov (Aze, 3); Vladimir Kramnik (Rus, 2.5) lost to Fabiano Caruana (Ita, 3); Michael Adams (Eng, 2) drew with Maxime Vachier-Lagrave (Fra, 2.5).