Oldham's play-off hopes were dented following a 1-0 defeat at Shrewsbury.
Will Boyle's first-half header proved to be the difference to leave Latics four points off the pace with four games to go.
Kane Drummond, Joe Garner and Fabio Jalo all saw chances to equalise go begging during an improved second half.
Taylor Perry and Iwan Morgan had early shots as the hosts started strongest.
Bradley Ihionvien scuffed an effort at the keeper before Kai Payne was unable to find the target midway through the half.
Boyle gave Town the lead on 30 minutes after getting on the end of Perry's cross.
Morgan curled wide shortly after the restart, before Matt Cox made an excellent one-handed save to leave Drummond frustrated.
Garner was inches away from an equaliser in the 55th minute after Jamie Robson's cross picked him out.
Ihionvien had a shot saved by Matthew Hudson's legs before Morgan's follow-up was also blocked.
Jalo cracked an effort against a post on 77 minutes to complete a miserable day for Oldham.
Report supplied by PA Media.
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