Keith Curle was denied his first three points as Latics Head Coach after substitute Jordan Hallam netted a last-minute equaliser to cancel out Alfie McCalmont’s strike.
Curle made two changes for the visit to the Sands Venue Stadium with Kyle Jameson returning from suspension alongside Callum Whelan making his way into the starting XI meaning Raphael Diarra and Brice Ntambwe were named on the bench.
Laurie Walker, making his second appearance of his emergency loan, was called into action in just the third minute as Devarn Green blasted a low effort on target, but the shot-stopper got down to deny the former Southport man.
And, not so long after, the MK Dons loanee produced another smart stop but this time to deny Alex Gilliead from giving the hosts the lead.
Dylan Fage nearly put his side ahead in an incredible fashion after neat one-touch football from Latics ended up at the Frenchman’s feet before he ambitiously curled an effort from around 30-yards, however, his attempt sailed just past Mark Howard’s far post.
The Iron continued to test Walker as Lewis Spence intelligently spray a pass across the field to the onrushing left-back Junior Brown, but the goalkeeper was equal to his long-range strike.
Keith Curle nearly witnessed his team taking the lead just before the interval as Marcel Hilssner’s deep delivery from a free-kick on the left-wing found the head of Jameson and the powerful defender flicked goalwards, but the goalkeeper managed to keep him out.
Moments into the second half, Latics took the lead through McCalmont as he netted his sixth goal for the club.
The goal arrived when Adams swung a corner into the box and, after a scramble, the ball was cleared but only as far as the Leeds United loanee on the edge of the box. He managed to strike the ball sweetly with his side foot, going through a sea of bodies before beating the goalkeeper.
Once again, Neil Cox’s side tested Latics’ goalkeeper with their captain, Jordan Clarke, fiercely striking from around 40-yards and Walker, initially, fumbled the attempt but succeeded in recovering and picked the ball up.
Following that, Kevin van Veen received the ball on the edge of the area before dribbling past Carl Piergianni towards the right-hand side of the box, but his low blasted effort was well saved by the Oldham goalkeeper.
Scunthorpe’s pressure continued to cause Latics problemswhen the ball landed at the feet of Green on the edge of the box, with his back to goal, he managed to quickly turn and shoot, but he saw his effort cannon off the crossbar.
In the last minute, Ryan Loft drilled a low effort on goal from distance, the ball swerved massively, however, Walker judged it well and parried it away.
The hosts found themselves level in the 92nd minute as a deep cross from the left found the unmarked Hallam at the back post and the substitute managed to keep composure to slot past the goalkeeper and into the back of the net.
Scunthorpe United XI: Howard (GK), Clarke ©, Bedeau, Gilliead, Loft, van Veen (McAtee 71’), Brown, Green, Spence (Hallam 79’), Karacan (Beestin 40’), Rowe (Howe 79’).
Subs: Watson (GK), Hippolyte, O’Malley.
Goal: Hallam 92’
Oldham Athletic XI: Walker (GK), Adams, Fage, Jameson, Piergianni ©, Badan, Whelan (Diarra 80’), McCalmont (Ntambwe 80’), McAleny, Keillor-Dunn, Hilssner (Grant 70’).
Subs: Bilboe (GK), Ntambwe, Tasdemir, Bahamboula, Da Silva.
Goal: McCalmont 49’
Referee: Sam Allison