United SC were reduced to 10 men just after half time with their star player Ranty Martins being red-carded by the referee.
After a goalless first-half, Lalrindika Ralte put East Bengal ahead in the 49th minute with a long range shot but minutes later all hell broke loose for the United SC as their ace forward Ranty was sent off after elbowing Saumik Dey inside the box during a throw-in.
Down with 10 players, United SC had little chance to bounce back and the red and gold brigade stepped up their gas with James Moga completing the rout in the 69th minute by connecting a Edeh Chidi pass.