A final-minute own-goal by an Eastern Railway striker helped holder Mohun Bagan beat the former 1-0 and continue its winning run in the premier division of the Calcutta Football League.
Playing in its home ground on Sunday, Mohun Bagan struggled to find the lead with a misfiring attack letting go a number of scoring opportunities.
Eastern Railway's Nigerian forward Abraham Fanny nodded an attempted clearance into own net to help the host escape with full points.
Having defended well for the greater part of the match, Eastern Railway appeared poised to hold its fancied opponent to a barren draw.
But a last-minute slip, which happened with Fanny's misdirected clearance on a Jayanta Sen corner, handed Bagan the points and a chance to stay in title contention.
The win took Mohun Bagan's tally to 16 points from seven outings while Eastern Railway remained at the bottom of the standings with four points from 11 matches. — Principal Correspondent