Two goals in either half saw Latics slip to another defeat against Leyton Orient at Brisbane Road.
Aaron Drinan and Tom James gave the hosts a half-time lead before late strikes from Theo Archibald and Harry Smith completed an afternoon to forget for Oldham, who were again hit by a host of absentees due to injury.
The result sends Latics to the foot of the Sky Bet League Two table and they know a marked improvement will be needed for the visit of Hartlepool United next weekend.
After a full week on the training ground, Keith Curle made three changes from the game against Barrow, Jordan Clarke returning to the defence and Rafael Diarra started in midfield.
Davis Keillor-Dunn went into the attack although Dylan Bahambula missed out having featured on international duty for Congo in midweek.
Orient built a solid half-time lead by striking twice on the break in the space of ten minutes.
Drinan put them in front, applying the finishing touch from close range after Archibald had turned defence into attack with a strong run from a Latics corner.
And James added the second shortly after, Darren Pratley releasing a pass from midfield, allowing the wing-back to cut in from the right and send the ball past Jayson Leutwiler.
Orient had carried a regular threat in the Latics half and they could have had more. Harry Smith sent an early header wide before Archiland broke again but this time lifted his effort over the bar.
Latics’ biggest danger in the first period came from Nicky Adams, who sent in a number of good crosses from the right but the visitors failed to capitalise.
Carl Piergianni was unable to make the most of a chance from a free-kick at the far post and later got his head to a free-kick from Faysal Bettache but directed the ball off target.
Hallam Hope was unable to connect with another cross from Adams after a good run down the right, while Jamie Bowden’s low 20-yard drive was saved by Lawrence Vigouroux.
Adams went off injured at half-time, being replaced by Harry Vaughan and within minutes he combined cleverly with Diarra on the edge of the Orient box but the visitors were unable to end the move with a meaningful effort.
The 17-year-old was soon involved again, displaying clever footwork and good vision as he took the ball out of midfield before teeing up Hope, who sent a curling effort wide of the far post.
Diarra brought a fine finger-tip save from Lawrence Vigouroux with a well-struck drive from 25 yards and the Orient ‘keeper also made a stop to deny Hope.
Despite the improvement in their play, Latics conceded again on 75 minutes, Archibald making the most of a mix-up between Clarke and Piergianni to send an angled finish into the bottom left-hand corner.
And Smith completed a miserable afternoon for the visitors, heading the rebound in from close range after Luetwiler had saved an initial effort from Dan Kemp.
Leyton Orient: Vigouroux, James, Wood, Happe, Clay, Smith, Archibald (Kemp 89), Mitchell, Drinan (Sotiriou 89), Pratley (Kyprianou 68), Beckles.
Subs not used: Byrne, Omotoye, Papadopoulos, Sweeney.
Oldham Athletic: Leutwiler, Clarke, Piergianni, Adams (Vaughan 46), Hope, Keillor-Dunn, Fage (Da Silva 85), Jameson, Bowden, Diarra, Bettache (Dearnley 79).
Subs not used: Danielewicz, Couto, Whelan, Luamba.
Attendance: 5,315 (379 away).