54-year-old Dhinakaran, who is contesting as an Independent candidate, is leading by a big margin followed by the ruling AIADMK's E Madhusudhnan; DMK candidate Marudhu Ganesh is trailing at number 3 after five rounds of counting. With Mr Ganesh, as its candidate, the DMK had hoped to send a message to the party cadre that ordinary workers too could rise to important positions in the party. Mr Ganesh comes from a family of DMK card holders; his mother was a municipal councilor between 1996 and 2001 when DMK working president Mr Stalin was the mayor.
Mr Ganesh's chances of winning were the brightest during the cancelled round of by-polls in April when the DMK had hoped the AIADMK votes would split between the two factions led by Chief Minister E Palaniswami and O Panneerselvam; the two sides merged in August this year. But the election was cancelled by the Election Commission after videos showing cash being paid to voters had emerged.
The RK Nagar battle symbolises the larger fight for the legacy of Jayalalithaa between her long-time friend VK Sasikala and her party the AIADMK. Mr Dhinakaran, who was the number 2 of AIADMK, was sidelined by the party after his aunt VK Sasikala got jailed in a corruption case, but both Ms Sasikala and Mr Dhinakaran claim to the legacy of Ms Jayalalithaa owing to Ms Sasikala's long association with "Amma".