Wigan are clinging to their Barclays Premier League status by the thinnest of threads after two calamitous defensive errors condemned them to defeat against Swansea.
Twice ahead through Roger Espinoza and James McCarthy, the Latics were floored by second-half goals from Angel Rangel, Itay Shechter and Dwight Tiendalli.
Defeat leaves Wigan three points adrift of safety with two matches left.
Their next assignment is Saturday's FA Cup final against Manchester City before they face a daunting trip to Arsenal next Tuesday, by which point their fate could be all but sealed depending on the results of their relegation rivals this weekend.
If the worst does happen, Wigan will no doubt look back with regret on a missed chance by James McArthur which would have made it 3-1 and perhaps taken the fight out of a Swansea side with little left to play for.
But Wigan manager Roberto Martinez must be acutely aware that no team can beat the odds when they inflict so many wounds on themselves.
Buoyed by Saturday's win at West Brom and knowing they would fire themselves out of the relegation zone with a win, Wigan had been expected to start with zest.
Instead they seemed to get stuck between an intent to attack and a nervousness about conceding.
In addition, the visitors had clearly done their homework on forward Callum McManaman, who has been in such good form recently, offering him little room on the right and seemingly happy to afford more freedom to makeshift full-back Espinoza.
The Honduran was pressed into service after Jean Beausejour joined Maynor Figueroa on the treatment table and his wayward early pass offered Wayne Routledge a sight of goal that Joel Robles saved.
Robles is set to lose his place to Ali Al Habsi at Wembley, and he almost cost his side in a most bizarre manner when he dropped on a back pass from returning skipper Gary Caldwell, which presented the visitors with an indirect free-kick barely seven yards out.
But as Wigan charged out from the goal-line, Ashley Williams lifted his effort way over the bar.
At the other end, Arouna Kone tried his luck from distance but too often he was an isolated figure.
Shaun Maloney schemed but failed to test Michel Vorm with a 20-yard free-kick which did not require the Swansea goalkeeper to move.
With Vorm also denying Kone's angled effort, the first half was meandering to a disappointing conclusion when Ben Watson lofted a high ball into the box.
But when Vorm leapt with Kone, the keeper only got a weak punch on the ball and Espinoza duly capitalised with a first-time volley that whistled into the tiniest of gaps at the near post.
Swansea returned from the break with more intent than they had showed in the opening period, penning their hosts back with their intelligent approach.
And when Routledge's precise chip dropped over Espinoza's shoulder, Rangel belted a superb shot in off the far post to make it 1-1.
Wigan needed a quick response and were level within two minutes as McCarthy strode onto Caldwell's through ball and drove it home.
McArthur would surely have wrapped up the points had he turned home Kone's cross but unmarked and just six yards out, the Scotland midfielder fluffed his lines.
How he had cause to regret that mistake as, in the face of concerted Swansea pressure, Caldwell turning from hero to villain with an abysmal pass out of defence, straight to Pablo Hernandez, who fed Shechter for the equaliser.
Vorm acrobatically turned over Caldwell's thunderous header as Wigan pressed, but the hosts pressed self-destruct moments later.
First Emmerson Boyce could have cleared but failed to, then McArthur and Maloney stood and waited for each other to scramble the ball out of their own six yard box. It was suicidal play, and Tiendalli, almost apologetically, prodded home the winner.
Swansea lost Vorm following a sickening clash of heads with Ben Davies, but Wigan's luck had by now deserted them.
With virtually his first touch after being introduced as part of a double change, Ronnie Stam got himself injured, which left the hosts to battle on with 10 men.
This time, the task was beyond them.