Karthik Thondaiman defeated his nearest rival Jahir Hussain of the DMDK, ensuring yet another cakewalk for the Jayalalithaa-led party which had earlier won Tiruchirappalli (West) and Sankarankoil bypolls held in 2011 and early this year since coming to power over a year ago.
Thondaiman romped home by a margin of 71,000 votes over Hussain, with the result increasing the AIADMK's tally in the 234-member assembly to 150.
The winning candidate polled over 1.01 lakh votes while Hussain secured a little over 30,000 votes.
The bypoll was necessitated by the death of Communist Party of India legislator SP Muthukumaran in a road accident.
The DMK, Marumalarchi DMK and other Opposition parties chose to stay out of the political contest following the AIADMK's emphatic victory in the previous Sankarankoil bypoll, leaving actor-politician Vijayakant's DMDK in the fray.
Reacting to the result, Vijayakant, also leader of the opposition in the state assembly, alleged money and muscle power behind the ruling party's win and said though its victory was "expected", the DMDK had contested to perform its democratic duty. His party had secured its deposit despite Jayalalithaa asking the people that it lost its deposit, he added.
DMK chief M Karunanidhi said he was "not bothered" about the AIADMK's performance.