Chennai, Nov 16 (IANS): Norwegian Magnus Carlsen, challenging defending champion Vishwanathan Anand of India for the chess World Championship title, won the fifth game in 58 moves after over five hours of a gruelling fight here Friday.

Two weak moves at a crucial juncture by Anand gave Carlsen the opportunity he was eagerly waiting for.

In the end, faced with Carlsen's two passed pawns, Anand was not in a position to prevent one of them from morphing into a queen and Anand threw in the towel.

In the post-match press conference, Carlsen said the first to win a game does not mean he would win the match.

The world title match is sponsored by the Tamil Nadu government and is being played at the Hyatt Regency hotel here.

Playing with white pieces, Carlsen opened with c4 - pushing his queen side bishop pawn two squares - which generally is called English opening. Anand responded with e6 - pushing his king pawn one square ahead.

"The game started as English opening but got transposed to a different line," Grandmaster S. Arun Prasad told IANS.

"On Carlsen's sixth move Nc3, the game entered into an unknown position. Carlsen must have done that to surprise Anand," India's number two-ranked Grandmaster P. Harikrishna told IANS.

On the 12th move, Carlsen castled on his queen side. Anand's 13th move of taking his bishop to c7 square was not a good step.

Come move 15, Carlsen decided to convert the opening position into a middle game by going in for queen exchange.

Both players had pawn weaknesses but white pieces enjoyed greater activity.

The game progressed steadily with experts saying that Carlsen enjoyed a minor edge over the champion when the number of moves were 30 in hand.

"Carlsen has brought the game to a position where only he can win or the game would end in a draw," Harikrishna said.

On his 45th move, Anand went in favour of giving a check to the white king with his rook which cost him one pawn.

From then onwards, it was downslide for the reigning champion.

Seven more games are to come and Anand has the advantage of making the first move playing with white pieces in the next two successive games.

While Carlsen has three points, Anand has two.

The next game will be played Saturday evening.

The game:

1. c4 e6 2. d4 d5 3. Nc3 c6 4. e4 dxe4 5. Nxe4 Bb4 6. Nc3 c5 7. a3 Ba5 8. Nf3 Nf6 9. Be3 Nc6 10. Qd3 cxd4 11. Nxd4 Ng4 12. O-O-O Nxe3 13. fxe3 Bc7 14. Nxc6 bxc6 15. Qxd8 Bxd8 16. Be2 Ke7 17. Bf3 Bd7 18. Ne4 Bb6 19. c5 f5 20. cxb6 fxe4 21. b7 Rab8 22. Bxe4 Rxb7 23. Rhf1 Rb5 24. Rf4 g5 25. Rf3 h5 26. Rdf1 Be8 27. Bc2 Rc5 28. Rf6 h4 29. e4 a5 30. Kd2 Rb5 31. b3 Bh5 32. Kc3 Rc5 33. Kb2 Rd8 34. R1f2 Rd4 35. Rh6 Bd1 36. Bb1 Rb5 37. Kc3 c5 38. Rb2 e5 39. Rg6 a4 40. Rxg5 Rxb3 41. Rxb3 Bxb3 42. Rxe5 Kd6 43. Rh5 Rd1 44. e5 Kd5 45. Bh7 Rc1 46. Kb2 Rg1 47. Bg8 Kc6 48. Rh6 Kd7 49. Bxb3 axb3 50. Kxb3 Rxg2 51. Rxh4 Ke6 52. a4 Kxe5 53. a5 Kd6 54. Rh7 Kd5 55. a6 c4 56. Kc3 Ra2 57. a7 Kc5 58. h4 Kd5 1-0