Edward Junior Wilson's 10th goal of the AFC Cup campaign had seen Padang cancel out Ryuji Sueoka's solitary goal from the first leg in Kolkata last week. But with 12 minutes remaining at Agus Salim Stadium, first-half substitute Moga headed home to put East Bengal ahead 2-1 on aggregate.
Marcos Falopa's side will play the first leg of their semi-final away from home next week after following in the footsteps of 2008 semi-finalists and fellow I-League side Dempo Sports Club.
Looking to add to their slender advantage from last week's first leg, East Bengal made a bright start and threatened to add to their slender one-goal advantage from several set-pieces inside the first 15 minutes.
But after Padang went close to a breakthrough after 20 minutes as a reflex save East Bengal goalkeeper Gurpreet Sandhu turned away Titus Bonai's close range flicked header, the home side levelled the tie on aggregate midway through the first half.
And having been the busier of the two goalkeepers, it was Sandhu's error which handed Padang the chance to draw level as his scuffed goal kick went straight to Wilson just outside the penalty area, and after the Liberian held off defender Uga Okpara the striker rifled into the top corner.
East Bengal's chances were dealt a further blow just before half-time as first leg goal scorer Sueoka was forced off with an injury, after the Japanese striker had earlier clashed with Padang goalkeeper Jandia Eka Putra, to be replaced by Moga.
Padang, though, endured their own injury setback at the start of the second half as Wilson was replaced by Muhammad Nur Iskandar.
Despite the blow, the home side remained the dominate force with Elie Aiboy twice coming close before Iskandar grazed the side netting with 15 minutes remaining.
But Padang were made to pay three minutes later as substitute Moga met a chipped cross from fellow substitute Baljit Sahni and powered an unstoppable header past goalkeeper Putra from the edge of the six yard area.
Needing two goals to save their AFC Cup campaign, Padang pressed in the closing stages, but were unable to find a way back into the contest as East Bengal maintained their unbeaten record in the competition this season.
--IANS (Posted on 24-09-2013)