The historic Indian club, tucked around the wide open spaces of maidans in Kolkata, advanced on aggregate (2-1) after holding Semen Padang to a 1-1 draw in the the return leg quarterfinal at the Agus Salim Stadium.
Playing in front of a packed home crowd, the Indonesian outfit started out aggressively and led at the half-time, thanks to a 23rd minute strike by Andrew Wilson.
For Joaquim Abranches and Abhijit Mondal, the success is all the more sweeter as they were also part of the Dempo squad that had played in the semi-finals of the 2nd tier inter-continental club competition a few years ago. Dempo till now were the only Indian football club to have made the last-four of the AFC Cup.
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Having started the game, Sueoka could only last 43 minutes and it was the Japanese midefielder's replacement, Moga, who struck the all-important goal.
Goan heavyweights Dempo had qualified for the AFC Cup semifinals in 2008.
East Bengal's previous best show in the AFC Cup was in 2004 when Subhas Bhowmick guided the side to the quarter-finals.