Former India defender and Mohun Bagan captain Manitombi Singh died at the age of 39 at his native village near Imphal in Manipur on Sunday, club sources said.
Manitombi was suffering from prolonged illness and breathed his last in the early hours of Sunday.
He is survived by his wife and an eight-year-old son.
“Mohun Bagan family is deeply saddened by the untimely demise of former club captain Manitombi Singh,” the club posted on its Twitter handle.
“Our thoughts and prayers are with his family during this difficult time. Rest in peace, Manitombi Singh,” it added.
Manitombi was a key member of the Stephen Constantine-coached India Under-23 side that lifted the LG Cup in 2003 by defeating Vietnam 3-2 in Ho Chi Minh City.
It was India’’s first international triumph since their victory at an eight-nation tournament in Singapore in 1971.
Manitombi also represented India in the 2002 Busan Asian Games.
The former right-back scored in his debut for Mohun Bagan at the Calcutta Football League Premier Division in 2003 and went on to lead the club in the All Airlines Gold Cup victory in 2004.
Having started out his playing career with Army Boys and Services, Manitombi also represented Air India and Salgaocar before making the big move to Mohun Bagan in 2003.
He was last seen playing for Manipur State League defending champions Anouba Imagi Mangal in the 2015-16 season before becoming their head coach.