World junior girls' champion D Harika beat English Grandmaster David Howell while Abhijeet Gupta and K Sasikiran suffered setbacks in the tenth round of the Corus chess tournament in Wijk Aan Zee, The Netherlands.
Sasikiran went down to Zahar Efimenko of Ukraine in Group 'B' while Abhijeet lost to Anish Giri in a Group 'C' match.
Harika kept herself in contention for a GM-norm, displaying fine attacking chess against Howell.
The Andhra girl, playing black in a Ruy Lopez opening, kept the Englishman under pressure and in his bid to force a spatial advantage, Howell blundered, allowing Harika to romp home in 48 moves. She is now tied for fourth place with 5.5 points in Group C.
Giving her company is compatriot Abhijeet, who suffered a jolt to Russian Giri, whose roots can be traced to India.
Abhijeet, playing black, blundered early against Giri in a Grunfeld defense game.
Giri managed to establish a minuscule advantage out of the opening and capitalised on a weak 15th move to reach a won middle game. Abhijeet sacrifice two pieces for a rook but it did not fetch much compensation.
The win took Giri to six points and third place.
Grandmaster Tiger Hillarp Person of Sweden stayed on top with 7.5 points after beating Frank Holzke of Germany.
Top seed Wesley So of Philippines remained on his heels with seven points defeating Roeland Pruijessers of Holland.
Sasikiran seems to have hit a rough patch and is finding it difficult to extricate himself from it.
The loss to Efimenko further dented his rating and the top seed Indian is currently at the bottom of the pool in Group B with three points from 10 matches.
Sasikiran's form deserted him again as Efimenko proved superior in a Nimzo Indian defense game. The Indian was on the receiving end in the middle game after missing a tactical sequence that left his king exposed.
Efimenko directed his pieces towards the kind side and launched an attack that saw him cruise home in 41 moves.
Important Round 10 results:
Group 'B': Nigel Short (Eng, 6.5) drew with Alexander Motylev (Rus, 6); Rustam Masimdzhanov (Uzb, 6) bt Francisco Vallejo Pons (Esp, 5.5); Krishnan Sasikiran (Ind, 3) lost to Zahar Efimenko (Ukr, 5.5); Erwin L'Ami (Ned, 5) bt Jan Werle (Ned, 3); Dimitri Reindermann (Ned, 4) drew with David Navara (Cze, 6); Yifan Hou (Chn, 4) drew with Fabiano Caruana (Ita, 6); Andrei Volokitin (Ukr, 6) drew with Henrique Mecking (Bra, 3.5).
Group 'C': Tiger Hillarp Persson (Swe, 7.5) bt Frank Holzke (Ger, 5.5); Roeland Pruijsseres (Ned, 3.5) lost to Wesley So (Phi, 7); Anish Giri (Rus, 6) bt Abhijeet Gupta (Ind, 5.5); David Howell (Eng, 5.5) lost to D Harika (Ind, 5.5); Manuel Bosboom (Ned, 5.5) bt Ali Bitalzadeh (Ned, 3.5); Friso Nijboer (Ned, 3.5) lost to Manuel Leon Hoyos (Mex, 4); Oleg Romanishin (Ukr, 3) lost to Eduardo Itturizaga (Ven, 4.5).