By Gabriel TanFollow @@gabetan13
Reporting from the Jalan Besar Stadium
Tampines fell behind in the 17th minute after Anaz Hadee scored an own-goal, but they equalised 11 minutes later when Sead Hadzibulic netted with a pinpoint header.
Nonetheless, East Bengal reclaimed the lead in the 62nd minute through Andrew Barisic, before Chidi Edeh made it 3-1 two minutes later with another close-range finish.
The Stags did manage an instant reply through Khairul Amri, who smashed home a volley from 12 yards out, but their hopes of a comeback were ended three minutes from time when Barisic steered home a Edeh cross to wrap up the win for the visitors.
The result leaves the reigning Great Eastern-YEO's S.League champions with just a point after three games, while their opponents remain top of the pile, ahead of Saigon Xuan Thanh on goal difference after the Vietnamese side defeat Selangor 2-1 in Wednesday's other Group H encounter.
Although a win would have been an acceptable result for them given they had already picked up four points from their opening two games, East Bengal were adventurous from the opening whistle and looked the more dominant side in the opening stages.
Six minutes in, they carved out the first chance when Edeh broke down the right and cut the ball back into the box, but Andrew Barisic opted for the dummy instead of a shot and allowed the opposition defenders to clear the danger.
Tampines then had a chance of their own in the 12th minute when Amri met a set-piece delivery with a deft header that bounced right in front of Abhijit Mondal, but the goalkeeper reacted well to block the ball with his feet.
But just five minutes later, the visitors took the lead after a corner was flicked on to Sanju Pradhan, who proceeded to rifle a shot towards goal. Anaz was on hand at the far post to block the shot but there was too much power on it, and the luckless full-back could only divert the ball into his own net.
East Bengal nearly doubled their lead in the 20th minute when Mehtab Hossain picked up the loose ball 35 yards out and sent a perfectly-weighted lob towards goal, forcing Sasa Dreven to tip over with his fingertips.
While the Red and Gold were enjoying plenty of possession, Tampines were looking dangerous in their forays forward and came close to equalising four minutes before the half-hour mark when a lovely right-wing cross from Imran Sahib picked out Amri at the far post, only for the Singapore international to lash a ferocious effort off target.
Two minutes later, however, the Stags were level after Shahdan Sulaiman received the ball from Imran and floated a glorious cross straight onto the head of Hadzibulic, who made no mistake in steering the ball into the far corner.
Shahdan then nearly created a chance for himself in the 33rd minute when he effortlessly skipped past Raju Gaikwad on the edge of the area, but he opted to beat another man before firing his shot away and was eventually dispossessed.
Right on the stroke of halftime, Mondal had to be alert to keep the scores level when he produced a smart save to keep out an excellent freekick from Shaiful Esah at his near post.
Dreven then nearly cost the Stags a goal eight minutes after the break when he needlessly raced off his line to confront Edeh and allowed the Nigerian to skip past him effortlessly. Thankfully for him, both Shaiful and Jufri Taha were alert to the danger and combined to block his goal-bound effort.
But there was little the Croatian custodian could do in the 62nd minute after Edeh, having seen his initial effort blocked by Anaz, kept the ball alive on the byline before cutting the ball back into the six-yard box, where Barisic was on hand to smash home from close range.
Just two minutes later, East Bengal's lead was doubled after they hit their opponents with a sweeping counterattack. Breaking down the right, Pradhan played a neat ball down the right to release Penn Orji, who immediately drilled in a low cross to pick out the unmarked Edeh. Left completely unmarked, the 25-year-old made no mistake as he emphatically fired the ball past Dreven for his side's third.
With their hopes of victory fast evaporating, Tampines needed a goal quick but they did just that 30 seconds later after Hadzibulic met a long ball and flicked it on to the Amri, who made the opposition defence pay for their momentary lapse in concentration by sending a powerful volley into the back of the net.
Buoyed at pulling one back, the hosts began to push more men forward but that left gaps at the back for East Bengal to exploit, and Dreven reacted well in the 74th minute to keep out a well-struck half-volley by Barisic, after the Australian had been picked out by Pradhan's visionary pass.
With six minutes left on the clock, the Stags then had a gilt-edged chance to equalise when Shaiful whipped in another dangerous freekick into the box, but with Mondal caught in no man's land, Amri could only steer his header narrowly over the bar.
And three minutes later, the contest was ended as East Bengal once again hurt their opponents on the counter; Edeh breaking free down the right before floating in a cross that took a slight deflection but fell to Barisic, who reacted well to meet the ball with his thigh and steer it past a hapless Dreven.
Tampines Rovers: Sasa Dreven, Anaz Hadee, Jufri Taha, Kunihiro Yamashita, Shaiful Esah, Imran Sahib (Firdaus Kasman 89'), Martin Wagner (Jamil Ali 71'), Shahdan Sulaiman, Ismadi Mukhtar, Sead Hadzibulic (Aleksandar Duric 82'), Khairul Amri.
East Bengal: Abhijit Mondal, Harmanjot Khabra (Gurwinder Singh 73'), Raju Gaikwad, Uga Okpara, Saumik Dey, Sanju Pradhan, Mehtab Hossain, Penn Orji, Lalrindika Ralte (Reisangmi Vashum 79'), Chidi Edeh, Andrew Barisic (Manandeep Singh 90').
Image courtesy of WSG