`I have ideas to regain the crown’

He said he was “very much still in business” and looking to win back from Kramnik his place as World No 1.

“I made mistakes but I have a future ahead of me and I have enough ideas to take the title back,” he said.

By way of explanation of his unusually poor performance against 25-year-old Kramnik in the championship, Kasparov, 37, said: “I see this as an unfortunate slip in my career.”

He added: “My preparations went wrong and my opponent had better preparations and robbed me of my good positions. At the time when I could balance the ship in game eight, I just burnt everything and that meant I had to work much harder 10 hours a day and, in the end, I was just very tired.”

There was no mention of personal problems that Kasparov had hinted about early in the tournament. Reports had suggested he was upset over a custody battle for his daughter or that he was shattered after his 1997 loss to the IBM Deep Blue computer.

Other observers, however, had come up with a far more convincing explanation: that Kasparov was beaten by an ice-cool, younger opponent, a chess genius in his own right who has been gaining in strength and finally overcame his master.

Kramnik, who pocketed 800,000 pounds in prize money for beating his former mentor, lent support to the idea that preparation was all important in the intense world of kings, rooks and pawns.

After previous tournaments where he made “terrible mistakes”, Kramnik said “it was clear I needed some physical training. I needed to be able to sit there for six to seven hours and I think that I did this well, I think I defended very well.”

But, having made it to the top, “I have a lot of responsibility now and I will have to play well in the future.”

The head of the Brain Games, Jeremy Hanley, said he was leaving it up to Kasparov and Kramnik to decide when and if they wanted a re-match.

Brain Games organisers also said that Kasparov-Kramnik game had been a big draw on the Internet, where it was broadcast live. During the month-long event, the webcasts attracted between 250,000 and 500,000 viewers at any one time, they said.