Norwegian challenger Magnus Carlsen was on Thursday just a step away from being crowned world chess champion winning a nail-biting ninth game against holder Viswanathan Anand in 28 moves and improving his lead to three points.
With this win, Carlsen took his tally to six points, and is just half-a-point away from becoming the new champion.
Interestingly, Carlsen did not move his white bishop, queen and king-side rook (except while castling) even one square throughout the game.
The queening of his 'b' pawn on the 27th move brought the game to a sudden end as Anand's attack vanished with the latter's one knight move.
"It was a tough game. There was a threat of getting mated," Carlsen told reporters post game.
Carlsen agreed that he missed some moves in the beginning to give Anand the attack.
With the looming threat of the world chess crown passing on to Carlsen, Anand went in for attack from the start.
Anand opened the game moving his queen pawn two squares to d4 and Carlsen replied with his knight move to f6 square in the ninth game of their title match sponsored by the Tamil Nadu government here.
The game progressed to Nimzo-Indian defence Samish set up with Carlsen, who normally blitzes in the opening phase of the game, spending time thinking.
"It is an unclear set up and usually the players do not get into end game phase quickly. They have to play the middle game. Anand seems to have come prepared for this match," India's second-highest-rated chess Grandmaster P. Harikrishna told IANS.
According to Harikrishna, Anand seems to have determined to play for a win making his moves fast.
It was Harikrishna who told IANS a couple of days back that Anand should avoid getting into endgame phase at an early stage.
"I don't know whether Anand and his team heard that. But it seems Anand did not have the time to make a change from his earlier strategy. After drawing last two games and a rest day, Anand seems to have changed his tact now," Harikrishna said.
"I needed to change the course of the match," Anand told media after the game when queried about the choice of sharp variation.
In their fifth move, Carlsen exchanged his black bishop for Anand's knight.
Anand started opening up his king's side, pushing his g pawn two squares forward. That did not deter Carlsen from taking his king to safety by castling on the king's side. Two moves later Anand castled on the same side.
Carlsen, trailing Anand in time, decided to focus on the queen side pushing his rook pawn forward with his knight already seated in b3 square.
On the part of the champion, the focus was on centre board and king's side.
Interestingly, except for Carlsen's knight all his other pieces were on the last rank.
At this juncture, Carlsen exchanged his knight on b3 square for Anand's black bishop. Anand captured the knight with his queen.
"Carlsen could have gone for exchange couple of moves later as well. But it seemed he wanted to play safe so that Anand's bishop does not come into active play," Grandmaster Humpy Koneru told IANS.
She said the position on the board after the knight-bishop exchange was equal and Carlsen was expected to open up play on the queen side.
As predicted by Koneru, the Norwegian brought his knight to c7 square and pushed his pawn to b4 square.
Anand obliged Carlsen's expectation of simplifying the position by exchanging pawns and one rook.
Pushing his pawn to f5, Anand continued with his king side attack. Anand had three pawns on the 5th rank.
"At this position white has to go for a checkmate as he has his e,f and g file pawns on the 5th rank. This is the position that Anand plays well and not exactly to the liking of Carlsen," Harikrishna said.
"After drawing last two games and a rest day, Anand seems to have changed tack now," Harikrishna added.
He said Carlsen's 22nd move b3 shows his understanding of the position though it seems black's king is under impending attack.
After long thought, Anand committed his queen to attack black's king moving the piece to f3 square and Carlsen immediately replied moving his knight to c7 square.
In the next move, Anand pushed his pawn on the f5 square to f6 threatening to open up black's king's defence.
Carlsen replied with g6 and Anand with g5.
Pressing further his attack, Anand moved his queen to h4 and Carlsen moved his knight to e8 square to come to his king's defence.
Replying to Anand's Qh6 move Carlsen pushed his pawn to b2 square to which Anand played Rf4. Carlsen then queened his pawn and gave a check. It was two queens on board for Carlsen.
Anand moved his knight before his king and Carlsen moved his new queen to e1 square sealing the champion's fate.
"I will try for three consecutive wins. But the situation does not look bright," Anand said.
White: Viswanathan Anand, India
Black: Magnus Carlsen, Norway
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 d5 5. a3 Bxc3+ 6. bxc3 c5 7. cxd5 exd5 8. e3 c4 9. Ne2 Nc6 10. g4 O-O 11. Bg2 Na5 12. O-O Nb3 13. Ra2 b5 14. Ng3 a5 15. g5 Ne8 16. e4 Nxc1 17. Qxc1 Ra6 18. e5 Nc7 19. f4 b4 20. axb4 axb4 21. Rxa6 Nxa6 22. f5 b3 23. Qf4 Nc7 24. f6 g6 25. Qh4 Ne8 26. Qh6 b2 27. Rf4 b1Q+ 28. Nf1 Qe1 0-1