The ruling AIADMK which was leading in Vellore Lok Sabha seat since Friday morning was pushed to the second place by arch rival DMK and the opposition party clutched the seat by a margin of 8141 votes.
While the DMK managed to secure a lead of 4,625 votes after the 10th round, it surged ahead subsequently and increased the margin to 7,895 votes.
The AIADMK was ahead by 3,162 votes at 11.40 a.m.
AIADMK's A C Shanmugam (chief of Puthiya Neethi Katchi, an ally of the ruling party) and DMK's D M Kathir Anand were the key contenders of the total 28 candidates in the fray.
The poll to the Vellore Lok Sabha seat, originally scheduled to be held in April along with the other constituencies in Tamil Nadu, was cancelled following tax raids here and cash seizures.
Fresh polling was held on August 5.