On-loan defender Jack Grimmer scored the only goal as Port Vale beat Oldham.
Teenager Grimmer headed home Chris Shuker's right-wing corner from eight yards out early in the second half.
Vale were fortunate to escape a first-half penalty box scramble, with Gary Harkins squandering the chance.
Jennison Myrie-Williamson should have put Vale in the clear but his 65th-minute penalty was brilliantly saved by Mark Oxley after James Dayton's trip on Tom Pope.
The home side suffered a blow with a serious injury to
debutant Florent Cuvelier,
when the loan signing from Sheffield United collapsed in agony after turning his knee.
The Belgian midfielder was stretchered off.
Vale, who extend their unbeaten home run to six matches in all competitions, are now three points off the play-off places while Oldham are two points above the drop zone.
VIEW FROM THE DRESSING ROOM
Oldham assistant manager Paul Murray told BBC Radio Manchester:
"There were some half chances but when we were going through [we need] to put someone in. We're just nearly there, we're not making that exact pass.
"Obviously we need goals to get the points, we're not scoring at the minute and we're conceding as well, so it's very upsetting and we'll endeavour to put it right.
"It was a rubbish goal to concede and we didn't even think it was a corner. And then it was just an out-swinger and no one's cleared it - it's disappointing."
Port Vale 01 Neal 20 Grimmer 05 Dickinson Booked 25 Cuvelier (Shuker - 36' ) 04 Robertson 17 Davis Booked 09 Myrie-Williams Booked (Birchall - 80' ) 21 Griffith 11 Pope (Hugill - 73' ) 19 Williamson 07 Loft Substitutes 02 Yates 08 Dodds 12 Johnson 15 Shuker 22 Lloyd 26 Birchall 39 Hugill Oldham Athletic 01 Oxley 12 Mellor 03 Grounds 19 Dayton (Worrall - 72' ) 06 Tarkowski 05 Kusunga 04 Wesolowski 08 Smith 27 Philliskirk (Clarke-Harris - 71' ) 30 Harkins 10 MacDonald (Petrasso - 71' ) Substitutes 09 Rooney 14 Clarke-Harris 15 Winchester 18 Lockwood 20 Petrasso 28 Worrall 29 Rachubka
Ref: Gary Sutton