Kolkata:Local International Master Saptarshi Roy scored an upset win over Russian Grandmaster Vladimir Dobrov in the fifth round of the third Kolkata Open Grandmaster Chess Tournament here.
Overnight leaders Grandmasters Nguyen Anh Dung of Vietnam and Czech Republic's Viktor Laznicka along with Bangladesh's Ziaur Rahman were in the number one position with 4.5 points at the Gorky Sadan.
Roy (4) opted for the Queens Gambit declined variation and won a few pawns, but his king was slightly exposed during the exciting match. However, he managed to wriggle out and eventually emerged triumphant against Dobrov, who remained on three points.
Dung and Laznicka faced each other on the top board, and took no risk before quickly agreeing to a draw in 21 moves.
Rahman seemed in fine form as he eased out Super Grandmaster Smbat Lputian of Armenia in 39 moves. The Bangladeshi managed to exploit the exposed king of his opponent in the endgame to win in a Reti opening.
Top seeded Krishnan Sasikiran played the Gunfeld Defence to perfection to pocket a full point over International Master Sundararajan Kidambi after a 62-move marathon.
In an interesting tussle, Grandmasters Koneru Humpy (3.5) and Sandipan Chanda (4) finished with a draw. Chanda, on the defensive from the outset, got his counter attack going in the endgame to force a draw by repetition.