East Bengal had to sweat till midway of the second-half before a Sanju Pradhan strike helped the defending champions beat Sporting Clube de Goa 1-0 in a Group C match and reach the semi-finals of the 30th Federation Cup at the Vidyasagar Krirangan in Barasat on Monday.
In an earlier Group C encounter, Jaspal Singh scored from the spot as JCT scored an identical victory over New Delhi Heroes.
East Bengal, with six points from two matches, needed a draw to advance and Pradhan ensured full points for the red-and-golds.
The match, being played under lights, was halted for more than 15 minutes after the changeover due to power failure.
The Kolkata giants struggled against a resurgent Sporting Clube de Goa who dominated much of the initial exchanges.
The current I-League leaders, who lost their Federation Cup group league matches 0-2 to JCT and 0-1 to qualifiers New Delhi Heroes, defended resolutely and created a number of opportunities only for their strikers to mess up.
After the change of ends, Sporting Clube almost scored through Micky Fernandes, but the midfielder missed the mark by inches.
At the other end, East Bengal's dangermen Sunil Chhetri and Yusif Yakubu had a lean day and it was left to Pradhan to drill home the winner.
Sunil was instrumental in setting up the goal. His neat little back flick found a surging Pradhan and the midfielder deceived Sporting Clube goalkeeper Gerald D'Mello to slot the ball home.