The result ended Bengaluru FC's unbeaten start to their first-ever I-League campaign but they remain top of the table for 24 hours at least with 13 points from six matches.
Meanwhile, East Bengal have successfully bounced back from successive defeats and now have six points from three games.
The heavy ground conditions due to the incessant rains made it difficult for both sides but East Bengal adapted the better and could have taken the lead early on when Cavin Lobo's cross found an unmarked Edeh Chidi inside the box.
However, the Nigerian's effort was blocked by former Middlesbrough defender John Johnson.
East Bengal looked very dangerous in the final third with strikers Chidi and Moga holding up the ball and setting up the runners from midfield.
But the Kolkata club was wasteful with their final ball and finish as they didn't test Bengaluru custodian Pawan Kumar too often.
Used to playing on the artificial turf of the Bangalore Football Stadium, the visitors struggled to retain possession in the first half but had a couple of good goal scoring opportunities.
Curtis Osano could only head it straight at East Bengal keeper Abhijit Mondal despite being unmarked from a Beikhokhei Beingaichho corner while the club's top scorer Sean Rooney slipped at the vital moment and could only attempt a weak shot after being played clean through on goal by Siam Hanghal.
The second half had an explosive start as Lobo rattled the Bengaluru crossbar with a thunderous effort from 30 yards.
Minutes later, the deadlock was broken as Bengaluru's second half substitute Robin unfortunately headed home Lalrindika Ralte's corner to give his former club the lead.
The India striker suffered more misfortune as he hit the woodwork after Abhijit failed to clear the danger following a Keegan Pereira cross from the left flank.
East Bengal had chances to double their advantage but both Chidi and Moga failed to convert. In one such opening, the two foreign strikers just couldn't attempt a shot on goal despite having plenty of time and space.
Bengaluru FC threw everything at East Bengal in the final quarter of the game with Rooney, Robin and India captain Sunil Chhetri all looking to equalise.
The away team put in plenty of crosses with East Bengal goalie Abhijit failing to collect many of those but no Bengaluru player could capitalise.
East Bengal finally sealed the points in the fourth minute of stoppage time when Moga finished off a counter attack with a powerful strike past Kumar to end the Kolkata club's four-match winless streak in Kalyani.
East Bengal 2 (Robin OG 49, Moga 90+4) beat Bengaluru FC 0
--IBNS (Posted on 26-10-2013)