Kolkata, May 15 (IANS) Teenaged Women International Master Vantika Agarwal of Delhi provided the biggest sensation of the ongoing Kolkata International Grandmaster Open Chess tournament when she defeated two-time national champion and Grandmaster Murali Karthikeyan of ONGC in the second round at the Newtown School here.

Ironically, the other biggest upset of the round came from a player at the opposite end of the age spectrum, as 55-year-old veteran International Master D.V.Prasad of Indian Oil Corporation defeated Grandmaster Deepan Chakkravarthy of the Integral Coach Factory.

Former World Junior champion Grandmaster Abhijeet Gupta was lucky to escape with a draw against teenager Raja Rithwick on the second board, while other creditable results of the day were by achieved by teenagers Sai Viswesh of India and Mohammed Fahad Rahman of Bangladesh who held Grandmasters Adam Tukhaev and Rohit Lalithbabu to draws, respectively.

Playing the black side of a Kings Indian defence, Vantika went in for a pawn sacrifice on the 30th move which did not look sound enough.

With both the players down to their last minute on the clock, she was rewarded for her risky play when Murali Karthikeyan blundered on the 36th move.

Fingers shaking, Vantika kept her nerves to effect a simple combination involving a Knight fork and won material to force a win in 42 moves.

In a surprisingly one-sided middle game arising out of a Ruy Lopez Chigorin variation, Prasad showed glimpses of his class as he made inroads into Deepan Chakkravarthy's kingside and steadily won material to win flawlessly in 49 moves.

Abhijeet Gupta was under pressure from the early middle game onwards, and was down a piece by the 42nd move. However, young Rahman couldn't keep his nerves in the final phase of the game and blundered back on the 54th move with a simple oversight to see his advantage evaporate.

The top seeded Nigel Short showed none of the fluctuations in form of Grandmaster colleagues around him, as he made short work of Women International Master Vaishali in just 21 moves to keep a full score. Thus, he kept his evening free enough to attend to his other passion of Cricket by leaving for Kolkata Knight Riders' clash with Rajasthan Royals late in the evening.

Twenty nine players have a full score of two points from as many rounds, as the battle hots up at the event. Seven more rounds remain to be played.