Wigan's hopes of progressing to the knockout stages of the Europa League were dealt a major blow with a 2-1 home defeat by Zulte Waregem.
Junior Malanda's 88th-minute winner means qualification from Group D is now out of the Latics' hands.
After Rubin Kazan and Maribor had drawn earlier in the evening, Wigan knew victory at the DW Stadium would be enough to guarantee their passage through to the last 32.
But they will now need to beat Maribor in Slovenia in their final group game next month and hope Zulte lose to Rubin.
The main sense of frustration for Owen Coyle and his players will be that the damage was largely self-inflicted.
Leon Barnett opened the scoring in the seventh minute and the hosts had no shortage of opportunities to extend their lead.
But they could not take any of them and in the 37th minute they shot themselves in the foot by allowing Zulte to equalise.
Loose play from Wigan set the visitors away on a break, and Lee Nicholls compounded the error by dropping Thorgan Hazard's shot into his own net.
Hazard is the brother of Chelsea star Eden and is on loan from Jose Mourinho's side, but his shot should certainly have been kept out by Nicholls, who had not had a save to make up to that point.
The Latics will now turn their attention back to the Sky Bet Championship and Sunday's visit of Derby, where Will Keane will provide Coyle with another option up front after signing on loan from Manchester United on Thursday.
Wigan came flying out of the blocks and it took them only seven minutes to make it count.
Callum McManaman tricked his way into the box on the right hand side and pulled the ball back for Jordi Gomez.
The Spaniard sliced his shot badly but the ball fell perfectly for Barnett, who produced a striker's finish by guiding his volley into the bottom corner.
It was the centre-back's fourth of the season but his first in European competition.
The directness of McManaman and James McClean on the wings was causing Zulte all sorts of problems and a second goal looked well within their grasp.
In the 13th minute, McManaman skipped past two defenders in the centre of the box and his shot was well saved by Sammy Bossut.
The goalkeeper was a busy man and soon after he was called upon to push behind a shot from McClean, who might have been better picking out Gomez as the Latics failed to make the most of a three-on-one break.
Nick Powell has been Wigan's main man in Europe, scoring three times, and he was the next to be denied by a block from Bossut.
Zulte had been on the back foot for the majority of the half but they shocked their hosts by pulling level eight minutes before half-time.
There did not look to be any threat as Barnett forced a corner at the other end, but Zulte cleared and a mix-up resulted in James McArthur sending the Belgians off on the counter-attack before the ball was played out to Hazard on the right of the area.
Nicholls opted to try to catch the Chelsea man's firmly-struck shot but it was a decision he regretted as the ball slipped through his hands and into the net.
Wigan only had themselves to blame, but they were nearly ahead again before half-time, Thomas Rogne glancing Gomez's corner across goal and wide when he really should have found the net.
Wigan were committing a lot of men forward and they were almost caught out in the early stages of the second half but Stephen Crainey did well to block Ibrahima Conte's shot.
The Belgians had settled into the game, and their small but noisy band of fans had high hopes when Hazard let fly again, although this time his shot did not trouble Nicholls.
Powell's first real chance arrived in the 61st minute as Steve Colpaert made a hash of clearing a cross from Crainey.
The on-loan Manchester United man struck his shot well from the edge of the box but it was too close to Bossut, who again produced a good save.
Gomez is often given a rough ride by the Wigan fans and there were loud cheers as he was replaced by Marc-Antoine Fortune with 26 minutes left.
Hazard was certainly the main dangerman as far as the Latics were concerned and his cheeky free-kick might have crept in the near post - understandably Nicholls was not taking any chances.
Both sides continued to push for a winner and McArthur was only a whisker away in the 79th minute with a shot just wide.
It was Wigan looking the more likely but they were hit with a sucker punch in the 88th minute as Malanda took aim from the edge of the box and found the top corner.