Danny Rowe scored twice to secure a fourth straight away win for Latics on a dramatic night in Cumbria.
On the back of his goalscoring exploits against Exeter on Saturday, Rowe bagged a brace as Harry Kewell’s side came from behind to take the points again at Barrow.
Trailing as early as the 16th minute, the visitors turned the game around to lead by the interval, but having then been pegged back in the second period, they sealed the win late on.
There was still time for Latics to concede again deep in added time but Kewell’s side were worthy of the points, consigning Barrow to their first home defeat of the season in the process.
It is six wins from eight for Latics in all competitions, meaning they head into the Emirates FA Cup tie at Bradford City at the weekend in strong shape.
It was against the run of play that the home side went ahead in the early stages, Scott Quigley turning well before curling home a 20-yard shot.
Latics had started brightly and they were able to keep their composure despite the concession of the goal. Bobby Grant could not have come close to an equaliser, breaking forward before drawing a finger-tip save from Joel Dixon, his angled shot hitting both posts before landing in the goalkeeper’s grasp.
Yet Kewell’s side found a deserved equaliser within a matter of minutes, Garrity continuing his knack of finding important goals from midfield by finding space in the box. Cameron Bothwick-Jackson picked out the run with a cross from the left, allowing Garrity to slide the ball home.
And Latics went ahead in added time before the break, glancing in a corner from Bobby Grant.
Ian Lawlor was called into action twice after the interval, first saving from Connor Brown after Matty Platt’s flick-on, before he denied substitute Dior Angus at the near post.
Piergianni also made an important challenge with Quigley bearing down on goal, but just as it looked as though Latics would be able to see the game out, their defence as breached.
With ten minutes remaining, Platt got on the end of a deep corner into the box to draw the home side level.
That was the cue for a frantic finale, Latics regaining the lead within seconds as Rowe rolled home a penalty after Dylan Bahamboula was judged to have been tripped by Yoan Zouma.
After period on the sidelines with a muscle injury, Conor McAleny marked his comeback as a second-half substitute with a goal, finishing smartly after a good ball across the area from Rowe.
With the eight minutes of added time having elapsed, there was still time for Barrow to score as Angus scrambled it home from inside the box but it could not prevent Latics returning home with a deserved win.
Oldham Athletic: Lawlor, Borthwick-Jackson, Jombati, Piergianni, Garrity, Rowe, Keillor-Dunn (McAleny 73), Grant (Blackwood 90), Fage, Diarra, Bahamboula (Barnett84).
Subs not used: Bilboe, Whelan, McCalmont, Hamer.
Barrow: Dixon, Brown, Brough, J Taylor (Taylor C Taylor 46), Platt, Jones, Quigley, Zouma, Biggins (Angus 72), Barry (Kay 61), James.
Subs not used: Lillis, Kay, Wilson, Reid.
Referee: Declan Bourne