Wigan Athletic matched promotion-chasing Oxford United at the Kassam Stadium for most of this fixture but a late defensive lapse denied them the point which would have taken them out of the relegation zone.
22-year-old striker Callum Lang had given the visitors a 57th minute lead but a Sam Winnall header had drawn the hosts level on 72 minutes.
But with only seven minutes of normal time remaining Latics centre-backs Curtis Tilt and Scott Wootton both hesitated inside the six-yard box and Elliott Moore had an easy task to tap the ball over the goal line for the winner.
Latics remain in the relegation zone and one point from safety while Oxford move up to seventh spot one point outside the play-off zone.
Leam Richardson named an unchanged starting eleven following the 1-0 victory against Northampton Town.
In-form Oxford had won 10 of their last 11 games and will believe they can still secure an automatic promotion spot.
In a very windy conditions and on a hard pitch Latics started the game brightly.
But the first real chance of the game fell to Alex Rodriguez whose 25-yard dipping strike tested Jamie Jones on 14 minutes.
Latics got into some good crossing positions but Tendayi Darikwa failed to deliver the final ball into the danger zone.
Full back Luke Robinson blazed over the crossbar following a long throw by George Johnston and Robinson supplied Wootton at the near post with a good cross but the centre-half headed wide at the near post.
0-0 at half time after a relatively uneventful first half with neither team creating any real clear-cut chances.
The half time interval was a more eventful affair as the match was interrupted for nearly an hour when the stadium had to be evacuated for a floodlight fire.
It could have been a disruptive factor but neither team seemed overtly affected by the extended half time delay and the second half had more goalmouth action than the first.
Robert Atkinson was allowed to drive to the edge of Latics’ penalty box on 54 minutes and forced a good save from Jones.
Three minutes later Lang put Latics in front with a smart-turn-and-finish from inside box after good work by Thelo Aasgaard and Johnston.
Curtis Tilt produced a great block to deny Winnall on 65 minutes as the hosts pressed for an equaliser.
But Winnall was not to be denied and from Brandon Barker’s pinpoint cross to the back post he headed Oxford level.
The hosts were upping their game now and Jones did well to tip over Mark Sykes strike from 25-yards out.
Darikwa’s first-time strike just veered wide of the target on 78 minutes as Latics looked to re-assert themselves.
The hosts measured build-up play was starting to have an impact and they were now dictating the game.
But it was a defensive mistake which allowed Oxford to take the lead. An innocuous cross from Sykes looked like bread and butter stuff for Tilt and Wootton inside the six-yard box but both men hesitated and when the ball dropped centre-back Moore was allowed the easy task of tapping the ball over the line.
Viv Solomon-Otabor and Zach Clough replaced Will Keane and Johnston on 85 minutes as the visitors went in search of the equaliser but in the last minute of added time Solomon-Otabor’s low cross was easily cleared and Latics slipped to a disappointing defeat.
It was a frustrating result for Latics who had played so well for much of the game against in-form opposition. They have another tough game against second placed Hull City on Wednesday night and they will need to eradicate all such defensive lapses if their to get anything from the game.