Top seeded Grandmaster Rustom Kasimzanov of Uzbekistan and Vietnamese Grandmaster Nguyen Anh Dung share the lead with six points each after the seventh round in the Commonwealth chess championship in Mumbai on Thursday.

Out of form Grandmaster Koneru Humpy (3) succumbed to another defeat, when she went down to Union Bank trainee Vikramaditya Kamble (4).

However, Humpy's younger sister Chandra Howsa, making her debut at the international level, shocked International Woman Master Bhagyashree Thipsay.

Grandmaster Dibyendu Barua's (5.5) attacking win over Ukrainian Grandmaster Ruslan Pogorelov (4.5) warmed the hearts of Indian chess followers.

Facing the Ukrainian's French Defence, Barua was at home as the Kolkata-based Grandmaster plays the same opening himself. Barua felt that Ruslan's 14th move of bringing the Queen in the centre was a mistake. Pogorelov lost a piece soon and Dibyendu Barua had no trouble claiming a point.

International Master Sekhar Sahu's (5) win over British champion R B Ramesh (4) was the surprise of the day. Veteran Sahu, playing after a long time and with the disadvantage of Black pieces gambled with a rarely played move in French Defence. It paid off handsomely as Ramesh played weakly and lost in just 18 moves.

Grandmaster Krishnan Sasikiran (5) survived a scare when he had to fight for a draw against Women's Grandmaster S Vijayalaxmi (5) in Grunfeld Defence. Vijayalaxmi won a pawn but had to settle for a draw after the Super Grandmaster from ONGC defended accurately.

Grandmaster Pendyala Harikrishna (4.5) faced a vicious offensive from J Ramakrishna (4). The Grandmaster gave a masterly display of his defensive skills and turned the tables on Ramakrishna.

Other important results: Igors Rausis (5) beat Murshed Nias (4), Fominyh Alexander (5) beat Deepan Chakkravarthy (4), Pravin Thipsay (5) beat Preethan Sharma (4), Babu Sudhakar (4.5) beat Hossain Enamul (3.5), Maxim Sorokim (5) drew with Dzhumaev Marat (5.5), Kotronias Vasilios (5) drew with Abhijit Kunte (5), Sandipan Chanda (5) drew with S S Ganguly (5).