World number one Magnus Carlsen of Norway cracked all-time high ratings, defeating Luke McShane of England in the first round of the London Chess Classic at the Olympia here.

The rating for Carlsen stood at 2851.2 points in the unofficial live rating portals which means that the Norwegian has cracked the all-time high rating record of 2851 held by former world champion and his former trainer Gary Kasparov of Russia.

On what turned out to be a perfect opener, all the four games in the nine-players round robin tournament ended decisively and the biggest upset was recorded by Hikaru Nakamura of United States who defeated World number two Levon Aronian with black pieces.

With Nakamura calling the shots, Vladimir Kramnik turned out to be another winner of the day at the expense of world's top woman player Judit Polgar of Hungary. The all-decisive-games record was kept intact by a late-benefitting Michael Adams of England against compatriot Gawain Jones.

World champion Vishwanathan Anand had a rest day in the opener as he drew number in the official drawing of lots.

The day belonged to Carlsen, 22, as he cracked something that Kasparov himself has termed as impossible when he got there many years back. A victory against McShane with black turned out to be the perfect start for the Norwegian who is often called the 'Mozart of Chess'.

The new rating itself is not enough as Carlsen would have to remain at his and world's all-time high till the end of the tournament as the next official list will be published only on January one next year.

The four victories mean that there are as many as four leaders with three points apiece under the soccer-like scoring system in place here that gives three points for a win and one for a draw.

With Anand remaining in the saddle in the opener, the world champion would like to catch up with the leaders when he takes on McShane in the second round.

Carlsen started with the in-vogue Berlin defense and McShane went for a symmetrical set up that gave him a miniscule advantage when the middle game arrived.

Not the one to shy away from complexities, Carlsen created chances for himself in the queen and minor piece endgame after coming back from the jaws of defeat and avenged a loss at the hands of McShane in 2010 at the same venue.

While Carlsen hogged the limelight, Kramnik punished Polgar for unwarranted complications out of an English opening with white.

Polgar gave a pieces in the middle game trying to find counter active measures but the postmortem revealed that Kramnik was always in control.

Nakamura was the biggest winner of the day as he could force his way against Aronian after getting a good position out of an English opening with black. Nakamura handled the fine prints in exemplary fashion.

The last game of the day was an all British affair between Jones and Adams in which the latter romped home, thanks to some overambitious play by debutant Jones.

The Queen and minor piece endgame should have been a draw but Jones tried to create chances for himself with a pawn sacrifice that boomeranged. The longest game of the day lasted 91 moves.

Results round 1: Luke McShane (ENG) lost to Magnus Carlsen (NOR); Levon Aronian (ARM) lost to Hikaru Nakamura (USA); Vladimir Kramnik (RUS) beat Judit Polgar (HUN); Gawain Jones (ENG) lost to Michael Adams (ENG).