World's youngest Grandmaster Parimarjan Negi struck back in style and defeated defending champion Grandmaster Jan Timman of Holland in the fifth round of Sigeman & Co. International chess tournament in Sweden.

After two losses in a row, Negi staged a fine recovery as he came back to a 50 per cent score at the approximate half-way mark of this Category-13 nine-round tournament.

Meanwhile, top-seeded Grandmaster Ivan Cheparinov of Bulgaria, who is better known as second of compatriot Veselin Topalov, continued with his excellent run defeating out of sort Jonny Hector of Sweden in a one-sided contest.

The victory was quite important in determining the lead positions as Cheparinov emerged as the sole leader after five rounds with a tally of 4 points.

Half-a-point behind the leader is the Swedish duo of Emanuel Berg and Tiger Hillarp Persson, who both drew their fifth round games against Dutchman Erwin L'Ami and Greek Vasilios Kotronias respectively.

The other game of the day was a quick draw between local hopefuls Emil Hermansson and Pontus Carlsson.

With four rounds to come in the round robin tournament, Negi is joint fourth along with Kotronias, L'Ami and Carlsson and in the remaining rounds the Indian will look forward to a positive score to get some valuable rating points.

Negi went for a tactical battle against Timman which was the need of the hour. Playing the black side of a Ruy Lopez, Timman was up against a topical variation that gave him enough play. But with the game remaining complex, the Dutchman was in for a surprise even when Negi was apparently short of time.

With under five minutes to make the last 8 moves, Negi spotted a fatal weakness in black's position and went on pressurising it with some fine deployment of forces. Timman made a vital error while trying to regroup his pieces and never recovered.

"It was quite a complicated game I think that could have gone either way", Negi said, adding "I think he missed out my moves towards the end and that proved vital."

Cheparinov was in his element in beating Hector in an irregular Sicilian of the day. Hector tried to confuse his younger rival in the opening but was surprised to find him at ease as the middle game approached and slowly caved in to some accurate play.

In other games of the day, Kotronias tried to find some holes in the position of Persson to no avail while Berg stood his ground without difficulties against L'Ami to get a half point with black pieces.

Results round 5: Emil Hermansson (Swe, 1.5) drew with Pontus Carlsson (Swe, 2.5); Jonny Hector (Swe, 1) lost to Ivan Cheparinov (Bul, 4); Vassilios Kotronias (Gre, 2.5) drew with Tiger Hillarp Persson (Swe, 3.5); Erwin L'Ami (Ned, 2.5) drew with Emanuel Berg (Swe, 3.5); Parimarjan Negi (Ind, 2.5) beat Jan Timman (Ned, 2).