The Congress on Friday increased its tally of seats in the Tamil Nadu assembly from 34 to 35 by wresting Madurai West seat, where its nominee K S K Rajendran trounced the All India Anna Dravida Munnetra Kazhagam's Sellur K Raju by 31,115 votes.

The result was also a shot in the arm for Dravida Munnetra Kazhagam patriarch M Karunanidhi's elder son and its pointsman in the southern districts, M K Azhagiri, who spearheaded the campaign for Rajendran.

The candidate of Congress, part of the DMK-led Democratic Progressive Alliance, was leading since the counting began at 0800 hours on Friday.

The by-poll, on June 26, was necessitated due to the death of rebel AIADMK member S V Shanmugham.

In 2006 polls, Shanmugham defeated a Congress nominee by over 3000 votes.

Azhagiri was in the eye of a political storm following the attacks on the office of Dinakaran, owned by Maran brothers, after the Tamil daily published a survey that claimed Azhagiri's younger sibling M K Stalin as a possible political successor to Karunanidhi.

The attack led to Dayanidhi Maran's exit from the Union Cabinet, also in the run-up to the polls. The results also showed the increasing popularity of DMDK, founded by film star Vijaykant, whose T Sivamuthukumaran occupied third position with 21,272 votes.