"This was not expected, but I knew that this song had the calibre to reach that level and get people's appreciation," said Mahadevan.
The song, which featured in the movie Chittagong, even won the best lyrics honour for writer Prasoon Joshi.
Mahadevan said the "classical-based song and was not promoted commercially".
"But I am happy that it was recognized by the jury members. I would like to thank the jury members," said the singer-composer, who already has three national awards in his pocket.
In the year 2000, he won the best male playback singer for Yenna solla poogirai, and four years later, he picked the best music direction trophy for Kal Ho Naa Ho, as part of the popular trio.
The year 2008 brought him yet another best male playback singer for the heartwarming track Maa from the film Taare Zameen Par.