Viswanathan Anand kept the World title after a 24-move draw in the 11th and penultimate game of the 12-game World Chess Championship final in Bonn, on Wednesday.
The Indian, playing with white pieces against Russia's Vladimir Kramnik, took an unbeatable 6.5-4.5 lead to retain his crown.
The game opened in a Sicilian Najdorf, as Anand was expected to go for a draw and Kramnik attempting to thwart all such attempts to try and force a victory that would keep himself in the match and take it to the 12th game to force a tie-breaker. But it ended in a draw as Kramnik failed to find a way for victory despite trying to complicate the game.
"Vladimir pushed me into giving my all. I've given one of my best-ever performances here in Bonn," Anand, 38, told the AFP news agency after victory was sealed.
"I tried everything, but it just wasn't enough. Life is like that and defeat is part of it," Kramnik conceded.
Anand earlier won three games, the third, fifth and sixth and lost the 10th in a match that looked one-sided till Kramnik brought back some life with a win in 10th game.
In the 11th game, Anand needing only a draw, managed that in a game that had a 1. e4 start and led to a Sicilian-Najdorf, which Kramnik rarely plays.
Kramnik went all out for a win and tried to create wild and unstable positions to throw Anand off-guard, but the Indian Grandmaster was up to the task.
In fact, as Kramnik overstretched in a do-or-die battle, he actually allowed Anand greater play and may well have lost.
According to the pre-match rules, the two players share the purse of 1.5 million Euros equally.
Even as Anand was celebrating his triumph and meeting the media, he received a message from Rajendra S Pawar, chairman NIIT, which has had a long-standing relationship with the Grandmaster for the last 10 years.
Pawar, in a message from Delhi, said, "We congratulate NIIT MindChampion, Vishy Anand on becoming the undisputed World Chess champion.
"Anand has displayed a grand strategy in 2008 by choosing the games that he wanted to win, foregoing an important tournament like Bilbao to focus on and win the ultimate match with Kramnik."
The moves:
Anand-Kramnik, Game 11:
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 Qc7 8. Bxf6 gxf6 9. f5 Qc5 10. Qd3 Nc6 11. Nb3 Qe5 12. O-O-O exf5 13. Qe3 Bg7 14. Rd5 Qe7 15. Qg3 Rg8 16. Qf4 fxe4 17. Nxe4 f5 18. Nxd6+ Kf8 19. Nxc8 Rxc8 20. Kb1 Qe1+ 21. Nc1 Ne7 22. Qd2 Qxd2 23. Rxd2 Bh6 24. Rf2 Be3 draw agreed.