The sides were evenly matched in the first half and were only split in injury time, when Callum Camps fired home to put Dale ahead at the break.
Dale dominated the second half and had a number of chances to score a second, but they were hit against the run of play when John Egan equalised with a header in the final fifteen minutes.
Keith Hill named an unchanged starting eleven from the victory over Blackpool on Saturday, as Dale looked to continue their impressive form. The only change was on the substitute’s bench, with Calvin Andrew returning from his injury lay-off to replace Rhys Bennett.
The opening stages were evenly matched, although there was heart-in-mouth moment for Joe Rafferty when his weak back pass found Bradley Dack. Fortunately for Dale, Josh Lillis was quick off his line to charge down the Gillingham man’s effort.
Joe Bunney saw his effort deflected out for a corner after he drifted in off the right side, beating a couple of Gillingham defenders as he shifted the ball onto his left foot.
There was a stoppage in play midway through the half as the fourth official was called on to replace the injured assistant referee, much to the amusement of those inside Spotland.
Dale had a great spell after the half hour mark in which they were unlucky not to take the lead. Firstly, Donal McDermott forced Stuart Nelson into a simple stop from distance, before the Gillingham goalkeeper turned Bunney’s deflected effort round the post superbly.
From the resulting corner came a great chance for Dale, when Oliver Lancashire glanced Michael Rose’s cross wide of the far post from a central position.
The visitors’ best chance of the half also came from a corner kick. An overhead kick from Adedeji Oshilaja fell to Luke Norris, who turned his header over the crossbar.
Three minutes of added time were signalled, and in the second of those Dale broke the deadlock. Nathaniel Mendez-Laing drove into the area from the right touchline and slipped a pass through to Camps. He beat a Gillingham defender and curled a left foot effort around Nelson to give Dale a half-time lead.
It was the perfect time to score and it gave Dale great confidence in the second half as they dominated the opening stages. McDermott and Bunney both saw headers wide shortly after the break, but Dale really started to turn the screw around the hour mark.
Bunney had a shot from the edge of the area deflected dangerously before being cleared. The forward then crossed from the right towards Camps who came inches away from making contact at close range.
McDermott’s last act on the pitch was to dribble past a number of Gillingham defenders brilliantly before forcing Nelson into a low save, with Camps sending the rebound over the crossbar from outside the area. McDermott was then replaced by Peter Vincenti to a standing ovation.
Vincenti was involved straight away as he rolled the ball to Mendez-Laing in the area, but the forward’s curling effort flew wide of Nelson’s left post.
With Dale in the ascendency for the majority of the half, the Gillingham equaliser came very much against the run of play. Substitute Jermaine McGlashan crossed from the right and Egan rose highest at the back post to nod the ball back across Lillis and into the net.
Keith Hill responded with two substitutions, Grant Holt and Andrew replacing Bunney and Mendez-Laing.
Andrew saw a header from a Rose free-kick fumbled around the post by Nelson, whilst at the other end Oshilaja had a looping header tipped over the bar by Lillis.
Vincenti sent a curling effort straight at Nelson, but the visitors played down the clock well and Dale couldn’t carve out that vital chance in the four minutes