Former world champion Viswanathan Anand yet again suffered a defeat against Hikaru Nakamura of United States in the 12th round and needs a Herculean effort to stage a comeback in the Candidates Chess tournament now underway. Nakamura has been Anand's nemesis for some time and another meeting between the two again brought out the best in the American who has otherwise had a forgettable Candidates. For the first 11 games, Nakamura had just scored a single victory, seven draws and three losses. The victory against Anand made his record slightly better but the American has no chance whatsoever of winning the Candidates. With just two rounds remaining in his biggest challenge of the year, Anand has a tall task on hand. In all probability, the Indian will have to win both his last two games to be in with a chance to challenge Magnus Carlsen of Norway in the next world championship match later this year. It won't be an easy task as Anand has to meet the seemingly impregnable Anish Giri of Holland and Peter Svidler of Russia. While he plays white against Giri, the black against Peter Svidler in the final round will still be tricky if Anand wins the next one. While the other games of the 12th round were still in progress, it looked as though Russian Sergey Karjakin was winning against Veselin Topalov of Bulgaria while Giri had the better position against another Russian Peter Svidler. Overnight leader along with Anand, Caruana Fabiano was evenly poised against Levon Aronian of Armenia. Nakamura got everything right at the start. Surprising Anand in another English opening in which the Indian lost to Caruana in 10th round, Nakamura was in control early as Anand was caught off-guard. In the post-match conference, Nakamura revealed that black's 11th move was a mistake when Anand saved his Bishop from a pawn onslaught. Getting in to a difficult situation by move 11 is not what Anand is used to and it was already difficult to find the most resourceful defences. As it happened in the game, Anand lost in just 26 moves. Results round 12: Hikaru Nakamura (Usa, 5.5) beat V Anand (Ind, 6.5); Sergey Karjakin (Rus, 6) playing Veselin Topalov (Bul, 4); Peter Svidler (Rus, 5.5) playing Anish Giri (Ned, 5.5) Fabiano Caruana (Usa, 6.5) playing Levon Aronian (Arm, 5.5). Aronian was calling the shots but misread his chances against Svidler who was spot on to cash in. After being in lead, this will be a tough challenge for Aronain to stage a comeback. Anish Giri played out his 11th draw on the trot. Against Hikaru Nakamura of United States, the Dutchman enjoyed slightly better prospects but could not sail through. In the other game of the day, Fabiano Caruana was close to winning against Topalov according to chess engines but the American did not read his chances well enough. Results round 11: V Anand (Ind, 6.5) beat Sergey Karjakin (Rus, 6); Anish Giri (Ned, 5.5) drew with Hikaru Nakamura (Usa, 4.5); Peter Svidler (Rus, 5.5) beat Levon Aronian (Arm, 5.5); Veselin Topalov (Bul, 3.5) drew with Fabiano Caruana (Usa, 6.5).