Five-time world champion Viswanathan Anand began his campaign in the Zurich Chess Challenge as he went down to Armenian Levon Aronian in the first round here.
It turned out to be a bad day in office for Anand who lost his way in the middle game and his counter-play bid did not materialise. The loss may prove quite costly as every win here is worth two points for the overall standings.
World champion Magnus Carlsen started from where he had left the classical chess. His last outing being the world championship match in Chennai, Carlsen did not show any rustiness coming back to the board and outplayed Boris Gelfand of Israel in a remarkable game.
The other game of the six-player round-robin tournament between Fabiano Caruana of Italy and Hikaru Nakamura of United States ended in a draw.
With four rounds in the Classical chess remaining and then five in the rapid stage to be played, Carlsen and Aronian emerged as the early leaders on two points each and they are followed by Nakamura and Caruana with a point apiece.
Gelfand and Anand will look forward to open their account in the second round.
The tournament has a unique format wherein the Classical and rapid scores will be clubbed together to find the winner. Every Classical win gives two points, draw one and a loss none while in rapid every win gives one and a draw a half point.
After tying for third and finishing fifth, Anand got a black to start the proceedings and Aronian came up with the English opening as an initial surprise. After the opening Anand was close to equal but Aronian ensured a consistent pressure on the queen side that increased after an error.
The Indian decided to part with a piece for three pawns but it was Aronian's day as he masterminded the ensuing endgame in copy book fashion. The technical issues remained and Anand fought on till the end but the Armenian gave nothing away and won in 73 moves.
Carlsen was at his technical best against Gelfand. The Norwegian chose to get a playable position as white and then, in his typical style, created huge complications that were hard to handle. When the dust subsided, Gelfand found himself two pawns less and the rest was child's play.
Nakamura and Caruana battled it out in a Grunfeld defense game wherein the latter as black got a level endgame and the draw was a just result despite a tough contest.
Results Round 1: Magnus Carlsen (Nor) beat Boris Gelfand (Isr); Levon Aronian (Arm) beat Viswanathan Anand (Ind); Hikaru Nakamura (Usa) drew with Fabiano Caruana (Ita).