Latics were left bitterly frustrated as Mansfield Town compounded the ‘boys in blue’ to another defeat on home turf.
Oldham had a promising start to the game as Jack Stobbs shaped a fine bit of individual brilliance to provide Keillor-Dunn with assist from the right-hand side.
Frustratingly, the Yellows levelled after the restart when Rhys Oates’ strike from the edge of the penalty area was deflected and found its way into the far corner before George Lapslie bundled in a winner in stoppage time.
With the visitors in search of back-to-back away wins, Shez opted for two changes from the midweek defeat against Sutton. Most notably, Carl Piergianni returned to the side after serving a two-match suspension and Dylan Bahamboula also returned.
As the sun beamed down on Boundary Park, both sides began the encounter with attacking intent which saw Oates cleverly cut inside from the left-wing before he drilled a low effort goalwards, but Danny Rogers comfortably denied the attacker.
In typical fashion, Nicky Adams delivered a pinpoint cross towards a towering Piergianni near the penalty spot with Nathan Bishop comfortably keeping hold of the skipper’s header, but it offered Latics positive signs.
Following that, Stephen McLaughlin raced down the left-hand side and illustrated immense vision as he sent Oates one-on-one with the Latics shot-stopper, but his low strike was excellently denied by the ‘keeper.
In the 24th minute, the terraces erupted as Keillor-Dunn put the hosts ahead after remarkably work from a teammate. Stobbs received possession towards the halfway line, and then, began a skilful dribble down the right-wing in order to supply an outstanding cross to the Sunderland-born man and he steered his header into the bottom corner.
Oldham were gathering momentum and forced the visitors into needless errors as the interval neared. Once again, Adams provided an impressive corner onto the head of Piergianni with the ‘keeper parrying the effort over the crossbar.
A half-time substitute, Jordan Bowery endeavoured to make an impact on the game, and he almost did just that within a minute of his introduction. The former Aston Villa striker picked up the ball on the byline before he selflessly pulled it back to Matty Longstaff inside the six-yard box, but somehow, Rogers kept him at bay.
Latics should’ve extended their advantage as Stobbs won possession inside the area, and then, laid it back to Keillor-Dunn, but the attack-minded individual fashioned a weak attempt which failed to cause the goalkeeper any real problems.
As it often is in football, Shez’s men were left to rue their missed opportunities with Oates finding the back of the net with a deflected effort in the 53rd minute to the joy of the away fans and the visiting dugout.
The Stags started to apply a vast amount of pressure and were nearly celebrating again when McLaughlin raced into the area, but his fierce low effort dragged past the far post. Then, a corner found Ollie Hawkins inside the six-yard box, and he instinctively flicked goalwards, only to be denied by Rogers.
In added time, Latics suffered more heartbreak as Mansfield clinched all three points courtesy of a substitute. Oates blasted his strike off the post before it hit an unmarked Lapslie inside the six-yard box and rolled over the line.
In the final seconds, the Stags were determined to remain tight at the back and they managed to see out the result which will be massive in their pursuit of the play-offs.
Oldham Athletic XI – Rogers (GK), Clarke, Piergianni ©, Adams (Hunt 67’), Whelan, Hope, Keillor-Dunn, Stobbs (Vaughan 74’), Bahamboula, Sutton, Couto (Fage 68’).
Unused Subs: Leutwiler (GK), Da Silva, Diarra, Hopcutt.
Goals: Keillor-Dunn 24’
Mansfield Town XI – Bishop (GK), McLaughlin ©, Hewitt (Bowery 46’), Murphy, Hawkins, Perch, Quinn, Oates, Wallace (Stirk 67’), O’Toole, Longstaff (Lapslie 80’).
Unused Subs: Stech (GK), Rawson, Johnson, Akins.
Goals: Oates 53’, Lapslie 95’
Attendance: 6,042 (1,321 away)
Referee – Ben Toner