Junior Luamba struck a dramatic winner to complete a late turnaround and secure Latics’ first league win of the season at Sutton.
Luamba netted in the sixth minute of stoppage time to earn Keith Curle’s side maximum points amid a frantic finale at Gander Green Lane.
Trailing with a minute of regular time to play, Latics eqaulised when Carl Piergianni’s header went in off a post before Luamba scored in front of the travelling contingent to send the fans into raptures.
With Latics pushing forward, Dylan Bahamboula set off on a charging run down the left before veering into the area. As he fed a cross into the centre, the ball broke to Luamba, who stabbed a shot past Dean Bouzanis from close range.
In Sutton’s first home game since promotion to Sky Bet League Two having had a new pitch installed, it had been a physical battle throughout for Latics.
Curle made one change from the side which progressed past Accrington in the Carabao Cup, Jayson Leutwiler making his debut in goal as the visitors also implemented a change of shape to include back four.
Harry Vaughan was handed his first league start in midfield, while Luamba retained his place in attack.
Buoyed by the sense of occasion, Sutton began with gusto and applied plenty of early pressure.
As early as the second minute, David Ajiboye broke forward before seeing a lot shot blocked, while Louis John headed over from a Rob Milsom corner.
Milsom also sent the ball in for Omar Bugiel to direct the ball over with another aerial effort and Enzio Boldewijn placed a dipping effort just wide of goal after a good break down the left.
It took time for Latics to settle, Luamba sending an effort past the target after Vaughan and Sam Hart combined down the left, but the visitors soon had to readjust after Hart picked up an injury and was unable to continue.
Curle’s side did carry a greater threat as the half went on, Clarke going close with a header before Dylan Bahamboula registered two shots, the first going wide after a great show of footwork before being denied by fomer Latics ‘keeper Dean Bouzanis.
Yet the home side remained a danger, Donovan Wilson latching onto a pass from midfield before miscuing as the chance opened up, while Ajiboye found himself in a great position in added time as an aerial ball came in but could only place his header wide.
Sutton retained their sense of purpose after the break, Wilson heading over a cross from Jon Barden before the hosts took the lead just after the hour.
Craig Eastmond unleashed a fierce shot from range which struck the bar, with Ajiboye quickest to respond to convert the follow-up.
Yet Latics kept on going and started to control an increased share of the play as the half progressed. Having been brought on after an injury for Dylan Fage, Faysal Battache send a long-range strike over the bar before Luamba brought a save from Bouzanis after an initial effort.
The afternoon looked to be ending in disappointmet for Latics until two dramatic late interventions.
Firstly, Piergianni’s header from a David Keillor-Dunn cross went in off the woodwork before Luamba struck late on, earning Latics a dramatic win.
Oldham Athletic: Leutwiler, Clarke, Hart (Sheehan 17), Piergianni, Whelan, Hope, Fage (Bettache 50), Diarra, Bahamboula, Luamba, Vaughan (Keillor-Dunn 46).
Subs not used: Danielewicz, Adams, Dearnley, Bowden.
Sutton United: Bouzanis, Barden, Goodliffe, John, Ajiboye, Bugiel, Beautyman, Eastmond, Boldewijn (Smith 85), Milsom (Wyatt 67), Wilson (Korboa 90).
Subs not used: Rowe, House, Kizzi, Bennett.
Referee: Darren Drysdale
Attendance: 3,262 (457 away)