Joe Rothwell was the match-winner as Rovers came back from the dead to rescue a win and secure their place in round two of the Carabao Cup.
It looked like Rovers were set to crash out of the competition when visiting captain Mohamed Maouche smashed home with just seven minutes remaining at a chilly Ewood Park.
But a Stewart Downing torpedo equalised for Rovers in added time before Rothwell tapped home from close range to salvage the result and sent Tony Mowbray's men through.
A disappointing first half display saw Rovers go in a goal down after Gevaro Nepomuceno's great effort, before substitute Bradley Dack equalised prior to Maouche's strike.
Greg Cunningham was handed his debut for Rovers in one of 11 changes as Mowbray's men looked to kick-start their campaign with progress in the competititon tonight on home turf.
Jayson Leutwiler started in place of Christian Walton, whilst a new look back four sees Academy graduates in Ryan Nyambe, Matty Platt and Joe Grayson joined Cunningham in defence.
Christopher Missilou had the first shot in anger, with the Frenchman sending a first time attempt over Leutwiler's upright from the edge of the box inside the opening 10 minutes.
But soon after the visitors took the lead through winger Nepomuceno, who picked up a stray John Buckley pass before advancing and firing low into Leutwiler's bottom left-hand corner.
Soon after and Missilou's near post header flew wide of target midway through the half as Laurent Banide's side continued to frustrate a new look Rovers team.
At the other end Corry Evans saw his strike somehow blocked on the line, before Alex Iacovitti did just enough to stop Ben Brereton from going one on one with Gary Woods after Danny Graham had played the 20-year-old in.
Athletic were the ones who held the lead going into the break, and in truth it had been a lacklustre first half display from the much-changed Rovers.
Mowbray's men did improve after the interval, with Brereton's header deflecting wide from Buckley's right-wing cross, before the same player used the same part of his body to nod Bradley Dack's deep cross goalwards before Zak Mills somehow stopped the ball going over the line.
Dack arrived on the pitch just after the hour and it only took the playmaker six minutes to make an impact as he smashed home the equaliser.
Grayson's hopeful ball into the box wasn't dealt with by Ashley Smith-Brown and after Graham proved to be a nuisance Dack was there to lash past Woods from 12 yards.
Dack wheeled away five minutes later when he thought he'd turned the score on its head, but after consulting with his assistant, referee Tom Nield bafflingly called for an offside decision and the goal was chalked off.
Harry Chapman's crafty pass found Dack, who would have found a quickfire equaliser were it not for a brave stop from Woods, before Graham and Dack linked up again, only for the Rovers number to see his shot agonisingly squirm wide of Woods' right-hand post.
It looked like time was running out for Rovers, but after latching onto a defensive header, Downing unleashed a terrific effort that flew into the bottom right-hand corner to level the score for a second time.
Time still remained for either side to secure a passage into round two and it was Rovers who did just that in dramatic style.
A high and hopeful punt forward found Graham, whose knockdown found Dack, whose intelligent touch fed Rothwell, with the number 8 tapping home to send Rovers through.
Rovers: Leutwiler, Nyambe, Platt (Chapman, 60), Grayson, Cunningham, Smallwood (Rothwell, 52), Evans (Dack, 63), Brereton, Buckley, Downing, Graham (c).
Unused substitutes: Walton, Williams, Gallagher, Rankin-Costello
Goals: Dack, 69, Downing, 90, Rothwell, 90.
Booked: Cunningham, 90
Oldham Athletic: Wood, Mills, Iacovitti, Sefil, Smith-Brown, Maouche (c), Nepomuceno (Branger, 66), Missilou, Fage (Hamer, 88), Azankpo (Wilson, 80), Sylla.
Unused substitutes: Zabret, Stott, Vera, Eagles.
Goals: Nepomuceno, 14, Maouche, 81
Booked: Maouche, 41, Smith-Brown, 70
Referee: Tom Neild.
Attendance: 5,215 (686 away)