Goals from S.K. Faiaz, Nikhil Kadam and an own goal by Shillong's Liberian defender Laurence Doe, ensured Mohun Bagan a place in the semi-final.
On April 17 they will take on the winners of the Friday quarterfinal between Bengaluru FC and Neroca FC.
While Shillong fielded Phurba Lachenpa in goal in place of Nidhin Lal, who had a brilliant Round of 16 game, and were attacking upfront with 19-year old Captain Samuel Lalmuanpuia playing just behind Ivory Coast's Abdoulaye Koffi.
Mohun Bagan began as the more aggressive even as the first shot at goal came off the feet of Samuel for Shillong as early as the fourth minute.
Faiaz then gave Mohun Bagan the lead in the 12th minute, which set off a very exciting next 15 minutes. Japanese mid-fielder Yuta Kinowaki passed ahead to Dipanda Dicka outside the box who chipped inside to Faiaz.
The winger chest-trapped it down and then got a second bite of the cherry despite being closed down by two Lajong defenders. His kick on the turn and while going to ground beat Lachenpa as the ball slotted into the right corner.
Ten minutes later, Doe headed a Faiaz cross clear, but only as far as Nikhil Kadam, 30-35 yards outside the Shillong penatly area.
Nikhil trapped and unleashed a curling left footer which beat Lachenpa all ends up and went in off the underside of the bar and came out. After some initial confusion, referee Santhosh Bhaskaran rightly blew to signal Mohun Bagan were 2-0 ahead.
The excitement continued as in the 25th minute, Bhaskaran adjudjed Kingshuk Debnath to have brought down Samuel inside the Bagan box and pointed to the spot. Samuel's shot was saved by the experienced Bagan keeper Shilton Paul.
In the 28th minute however, Shillong got their goal back, when a chip from the mid-field found Samuel inside the box, whose lobbed voley while going to ground and with his back to the goal, was headed over Shilton's hands by an onrushing Koffi.
Bagan went into the lemon break maintaining their one goal advantage.
A young Shillong side's game was clearly in the ascendancy in the first quarter of the second half as they were attacking purposelfully and created a few good chances. All that changed in the 60thminute, when talented right back Arijit Bagui on the overlap, floated in a cross aimed at Moghrabi inside the Lajong box.
Both Akram and Doe went for the ball with different purposes, but unfortunately for Doe, his header in trying to clear the ball lodged inside the Shillong goal.
The goal came against the run of play but Mohun Bagan took complete control after this and went on the charge taking smart advantage of the two-goal cushion.
Shillong Lajong FC tried to put together a few attacks in the last moments of the game and Abdoulaye Koffi got a chance to pull back a goal in the injury time as well but Mohun Bagan managed to hold on till the end and the match ended with the score at 3-1.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)