Chesterfield's relegation fears increased when they allowed a patched-up Oldham team to hit back and take a point from a shapeless match at Saltergate.
The Spireites Steve Blatherwick punished a goalkeeping error to put his side into a 29th minute lead, but Calvin Zola capped an improved second-half display from the visitors with a 55th minute equaliser.
After that Chesterfield had plenty of the ball but did not manage a shot on target in the second half as the precious points slipped away.
Oldham will be pleased to take a point and in Zola had a player who was capable of making something from nothing.
He might have won them the game if Les Pogliacomi had not totally misjudged Allan O'Hare's 29th minute corner.
Blatherwick was presented with a free header and he made no mistake, but the Spireites could not take full advantage of that gift.
Oldham had created little before the break but they were sharper in the second half and Zola almost headed them level in the 51st minute.
A cross from Dean Holden found the on-loan Newcastle striker eight yards out and his downward header looked certain to go in until Carl Muggleton somehow turned the ball over the bar.
But Zola was celebrating four minutes later when Holden sent him away down the left channel and he beat the advancing Muggleton with a low left-foot shot from the edge of the area.
It was a neat finish but neither side could find another. Chesterfield brought on strikers Jamie Cade and Marvin Robinson but Oldham defended well.
Zola had another header near the end, but he failed to get any real power on the ball and Oldham were clearly content to play out a draw.
Chesterfield kept pressing but Pogliacomi did not have another save to make and the result leaves the Derbyshire club deep in the relegation mire.