Amit Mitra smiled and flashed the occasional V-sign as he walked down the pathway of Guru Nanak Institute of Technology in Agarpara - some 4km from his constituency, Khardah - where the counting was on.

By the end of the day, the economist-turned-politician emerged victorious by defeating his senior at Calcutta University, Asim Dasgupta of the Left, by 21,200 votes.

Mitra had defeated Dasgupta by 26,154 votes in 2011 but he wasn't so sure this time, party workers say.

He was tense even on Thursday morning, not wanting to step out of his house till he got positive reports from the counting centre, a party worker said.

In the run-up to the polls, Dasgupta - unfazed by his defeats in the 2014 Lok Sabha polls and the 2015 Salt Lake municipal polls, when the Left had pitched him as the mayoral candidate - was found campaigning in the lanes and bylanes of Khardah, a former red bastion, with zeal.

A Trinamul insider said things came to such a pass that Mamata Banerjee called up some leaders in Khardah before the polling date, asking them to ensure her finance minister's victory.

On polling day, April 25, Mukul Roy, one of Trinamul's all-India vice-presidents, is believed to have called up some of the party functionaries, seeking a ground report. The last call of the day had come from the chief minister's nephew and Trinamul Youth Congress chief Abhishek Banerjee - Mitra must defeat Dasgupta, his predecessor in the Left regime.

And win he did. Rural Khardah, comprising parts of Patulia, Bandipur and Bilkanda backed Mitra. Roads, lights and water connections triumphed over Narada tapes and Saradha scam, a party worker said.

"My victory or its margin is not important. I am just a soldier in Mamata Banerjee's team, which will script a new history for Bengal," Mitra smiled. "This verdict will help set up a new matrix of regional parties in the 2019 Lok Sabha polls. Bengal will again witness a renaissance," he added.