Mumbai: Giant-killer R. R. Laxman of Chennai upset GM Saidali Iuldachev of Uzbekistan in the fourth round of the Commonwealth Chess Championship here Tuesday.

After the end of the round, Russian GMs Pavel Smirnov and Alexander Fominyh joined India’s Pendalya Harikrishna in the lead with hard fought victories over double IM norm-holder Saptarshi Roy Chowdhury of Calcutta and George Michelakis of South Africa, respectively.

The three leaders have 3.5 points followed by a pack of 26 players. Those in the joint second spot include top seed Nigel Short of England, K. Sasikiran and Surya Sekhar Ganguly.

Short beat IM Prathamesh Mokal, while Sasikiran and Surya drew with Harikrishna and Chandrashekhar Gokhale, respectively. Among Bengal players, Sandipan Chanda (2.5) won his game. Saptarshi Roy (2) lost to Humpy, Atanu Lahiri (2) lost to Sergei Iskusnyh, Neelotpal Das (2.5) drew with Vladimir Feldman, while Somak Palit (3) beat S. Sai Krishna. Nisha Mohota (2.5) drew with N. Vinuthana.