They had to settle for a 1-1 draw against relegation-threatened Notts County, but clubs chasing a play-off place missed the opportunity to close the gap.
Seventh-placed QPR were held 2-2 at home by relegation-threatened Mansfield, while Tranmere moved onto the same points as eighth-placed Blackpool by virtue of beating the Seasiders 2-1 at Prenton Park.
Luton slipped back after a 1-0 home loss against Brentford.
Home malaise
The Latics had already scored six goals in two league and cup games against the visitors this season and, if anything, they should have used this third meeting to hit double figures.
But the home sickness which is slowing their promotion progress struck again.
Iain Dowie's high-fliers have now won only one of their last eight games at Boundary Park, for a miserable return of just seven points.
Little wonder then that the fans showed their frustration at the end. Dowie said: 'I was disappointed at their reaction because the lads don't need to face all that anxiety.
'Fans must be supportive'
'The fans need to be supportive at home ' they are superb when they follow us away.
'If we had drawn at Stockport last week and won this one, everybody would have said we have done well to take four points from the two games.'
There was nothing wrong with the football, it was simply that they couldn't finish off a well-beaten side.
Oldham had 18 shots to County's six, but Wayne Andrews' sixth goal of the season just before the break was cancelled out by a leveller with five minutes to go.
Dowie admitted: 'Our finishing let us down and we have to start making the most of our chances.'
Will Oldham's home form cost them promotion? Have your say.
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