Skipper Sunil Chhetri (26th minute) and Harmanjot Khabra (49th) were the scorers for Bengaluru, who secured their second win on the trot to make it 24 points from 16 matches.
The visitors had beaten another northeastern side, Aizawl FC, in a home match before coming for the Shillong tie.
Lajong, meanwhile, will have their task cut out in the remaining two matches if they still fancy a top three finish in the season. They have droped to the fifth spot with 24 points.
Lajong let go a couple of half-chances within the first 20 minutes to allow the visitors to put up an even battle on the pitch.
The three tall Bengaluru backline -- Juan Fernandez, John Johnson and Ranjan Singh, made life difficult for the Lajong forwards, especially the in-form Dipanda Dicka. The trio also almost took the aerial ball out of the equation as far as Lajong are concerned thus restricting the nature of the raids.
In the 26th minute, captain Chhetri secured the crucial lead for Bengaluru. An unmarked Chhetri collected a neat ball from just outside the box and placed it to perfection to the far right net as a valiant Vishal Kaith dived in vain.
Barely six minutes later, Dicka had a great chance to restore parity but his header of an Issac Vanmalsawma free kick missed the target by a whisker.
Dicka missed another half chance in the 36th minute when he failed to reach out for a fine Samuel Shadap cross from the right.
The tall Bengaluru defence prompted Lajong coach Thangboi Singto to bring in Brazilian Fabio Pena straightaway in the second half. However, before Lajong could settle down the visitors doubled the lead in the 49th minute, this time through Harmanjot Khabra who sent a low header past Vishal following a cross from the left.
Two minutes later Alwyn George almost made it 3-0 but his shot went just wide on the left.
Post the hour mark the Lajong legs looked a touch sloppy and the result seemed a foregone conclusion by the 80th minute.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)