Top seed Parimarjan Negi of India suffered a shock defeat at the hands of compatriot N Srinath in the third round of the Under-12 boys' section at the World Youth Chess Championships in Belfort, France.
Negi's first defeat may prove costly. He will lose some important rating points as Srinath was nearly 300 points behind him.
In the Under-16 girls' section, top seed D Harika was also in for a surprise, being held to a draw by Katherine Pelletier on the top board.
Other Indians had mixed results in 10 different categories of the event.
Sahaj Grover maintained his lead in the Under-10 boys' section with a clinical victory over Nikita Krayushkin while V A V Rajesh continued to make his presence felt in the under-12 category by defeating Aplin Christer to maintain a clean slate.
In the under-14 boys' section too, India's best bet Y Sandeep continued to be amongst the leaders with a cent percent score. On the receiving end against Sandeep in the third round was Charles Baudson.
Amongst the Indian girls, Saheli Nath emerged the group leader in the Under-16 section after smooth sailing against Mathilde Congiu in her third round game.
Negi apparently was coasting home with black pieces against Srinath when disaster struck him in the middle game.
Playing the Sicilian Nazdorf, he was up against an English attack and his preparation came good as he was able to launch his offence on the white king side while his opponent was getting ready for a similar attack.
However, as the game progressed, Negi went for an erroneous plan that put Srinath in a slightly advantageous position.
Srinath let go a rook for a direct attack and did not falter in picking the black queen a few moves later for another rook.
Negi, having lost a handful of pawns also in the process, hardly had any chance to recover thereafter and he called it a day on the 43rd move.
Harika survived some anxious moments before she took the draw with Pelletier, who played the white side of Sicilian Nazdorf.
The Indian even had a dangerous looking passed pawn in the centre but fine planning by her opponent led to a rook and opposite colour endgame wherein Harika was a pawn down.
Surprisingly Pelletier opted for a safe route to split the point rather than pressing hard for a win.
Y Sandeep was a bit lucky to win a pawn less endgame against Baudson in 76 moves while Saheli Nath used her Pirc defence to good use against Mathilde Congiu to win in 58 moves.
Indian results (Round 3):
Under-10: Nikita Krayushkin (2) lost to Sahaj Grover (3); Shiven Khosla (2) lost to Daniel Naroditsky (3); Rishi Thariani (2.5) beat Tomas Laurusas (1.5); Surya Sudarshan (1) lost to Oliver Zier; Pierre Barbot (1) beat Subodh Shirodkar (0); Christophger Hueng (1) lost to K Harsh (2); Vasant Varman (2) beat Stefen Beukema (1).
Under-12: N Srinath (3) beat Parimarjan Negi (2); S. P. Sethuraman (2) lo0st to Zhao Parker (3); Jon Aplin Chirster (2) lost to V. A. V. Rajesh (3); Prasanna Rao (2) beat Aleksandar Dimovsky (1); Patrick Zelbel (1.5) drew with Hari Hara Sudhan (1).
Under-14: Charles Baudson (2) lost to Y Sandeep (3); Niclas Huschenbeth (3) beat Sankalp Modwal (2); Nikhil (1.5) beat Dadi Omarson; T. Pranav (0) lost to Jeam-Marc Depaz.
Under-16: Andrew Green (1.5) lost to G Rohith (2.5); Alex Renderman (2.5) beat K Vijaya Keerthi (1.5); D Sai Srinivas (2) beat Pavel Rakus (1).
Under-18: Ante Berkes (2) beat Deep Sengupta (1.5); Nikkolaj Mikkelsen (2) lost to Deepan Chakkravarthy (2).
Under-10: K. Sai Nirupama (2.5) beat A Botez (1.5).
Under-12: Jus Katza (1.5) drew with P. Lakshmi Sahiti (1.5) bt Arina Hohluka (0); Molly MCgarity (1.5) drew with Rucha Pujari (1.5); Marina Brunello (0) lost to G. Srisha (1).
Under-14: Laura Fernandez (3) beat I. Ramya Krishna (2); Fayega Bukhashem (1.5) lost to Pon. N. Krithika (2.5).
Under-16: Katherine Pelletier (2.5) drew with D. Harika (2.5); Mary Ann Gomes (1.5) lost to Naomi Miller (2.5); Mathilde Congiu (2) lost to Saheli Nath (3).
Under-18: Maka Purtseladze (3) beat Soumya Swaminathan (2); N Vinuthna (1.5) lost to Eva Kulovana (2.5).