Grandmaster Krishnan Sasikiran finally managed to score a much awaited victory against GM Tomasz Markowski of Poland in the fourth round of the Aeroflot International Open Chess tournament.

Grandmaster Andrei Kharlov of Russia [Images] created the biggest upset of the event defeating second seed and hot favourite Vassily Ivanchuk of Ukraine.

The Russian thus shot in to sole lead with 4 points in the 'A-1' section that carries a winner's purse of USD 30,000.

Former champion Viktor Bologan of Moldova, Alexander Areshchenko of Ukraine and Israeli Emil Sutovsky are close on the heels of the leader with 3.5 points each while a pack of 11 players are on 3 points.

Amongst the Indians, National champion and Grandmaster Surya Shekhar Ganguly moved to 2 points along with his Kolkata city-mate Sandipan Chanda while Sasikiran edged himself up to 1.5 after his finely crafted victory with white pieces.

Day four of one of the strongest open tournaments of the world proved a better one for the Indian contingent as most gave an improved performance.

Ganguly again held a higher rated opponent -- Evgeniy Najer of Russia -- to a draw while Sandipan Chanda also did a similar act and split the point with Alexei Fedorov of Belarus in the 'A-1' section.

In A-2 section, Grandmaster Tejas Bakre was held to a draw by Ruslan Yandarbiev of Russia while young gun Parimarjan Negi held Oleg Chebotarev.

First time winners in this group were S Kidambi and Eesha Karvade, who both scored emphatic victories over Kirill Kuderinov of Kazakhstan and Ekaterina Korbut of Russia respectively. The lone Indian loser of the day was Tania Sachdev who succumbed against Evgeny Romanov of Russia.

In Group 'B' Dinesh Kumar Sharma drew with Hrant Melkumyan of Armenia.

Ganguly came close to winning against Najer but the Russian hung in there with some precise defence. It was the open variation of the Ruy Lopez wherein Ganguly got a tangible advantage in the middle game.

After launching an attack on the king, Ganguly faced stiff resistance as Najer exchanged pieces at regular intervals to arrive at a pawn less rook and pawns ending.

However, as it turned out in the end, Ganguly could not convert his extra material to a full point and signed peace in 57 moves.

Kharlov punished Ivanchuk for his over-ambitious play.

Right from the beginning, even though he played black, Ivanchuk went for uncompromising play and even managed to get an advantage as Kharlov played passively.

However, in his bid to improve the middle game position further, Ivanchuk had to pay heavy price for his fractured pawn structure. After the dust settled, Kharlov emerged a pawn up in a double rook ending and in no time turned the tables on Ivanchuk. The game lasted 59 moves.

In other important games of the day, Sutovsky was in top form in a brilliant tactical victory over Valerij Filippov of Russia; Bologan proved much stronger than Luxemburg's David Alberto while Areshchenko cruised past former World Junior champion Shakhriyar Mamedyarov of Azerbaijan.

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