Kramnik holds the stage as Kasparov sulks

Russia's Vladimir Kramnik took a feather out of reigning world champion Garry Kasparov's cap when he forced him to accept the queen's gambit before the two settled for a draw after a marathon fourth game of the BrainGames World Chess Championship in London on Saturday night.

The much beaten Grunfeld Defence was set aside as Kasparov resorted to defending the queen's gambit -- a real surprise as he rarely accepts facing this kind of format.

As Kasparov and Kramnik split the point after 74 moves, the challenger held a clear one-point lead, 2.5-1.5, in their 16-game match-up.

Kasparov, sulking at having let Kramnik off the hook in the second game, killed a White pawn on the second move. Kramnik returned with fire on the fifth and then castled his king to let Kasparov open his defences.

A fierce middlegame was in the offing with White contracting an isolated queen's pawn in return for attacking chances. This put Black under heavy pressure, but White's next move removed most of the tension as the game moved into a somewhat simplified position.

Kramnik, who slipped one position to world number three as India's Viswanathan Anand took over his place, handled the arising variation perfectly.

As both players moved quickly and the tension eased, the game looked to be heading for a draw after only 15 moves had been played.

Kramnik could have guaranteed a draw for himself by playing 18. Nd4, but he went for 18. Rac1 showing he still had something up his sleeve.

White had the intention to chase back Black's pieces with a kingside pawn rush as even in a highly simplified position the space gain could have brought White an advantage.

Kasparov had to retreat a bit, but carved out some space for himself on the queen's flank.

As Kramnik gained an edge, he started threatening Kasparov in the hope of going for another kill of the champion.

A fired-up Kasparov, instead of defending passively, lashed out and opened the position up and brought the material advantage at level with half an hour left for both.

Kramnik continued with his threats, getting more concrete than ever, as White sought salvation by entangling his pieces after a web of checks.

As time started to play its role, inaccuracies crept in. Kramnik played 38. Kf3 instead of going for the winnable Nf4, allowing Kasparov to hold the balance.

Kasparov used all his thinking power to create some counterplay by issuing a check with his knight. Kramnik gambled with Ne4 and Kasparov regrouped his resources as White lost his final chance to earn a full point.

The endgame of rook and knight against knight petered into a theoretical draw.