Wigan's James McArthur tapped in a second-half winner to help the basement side move to within a point of neighbours Bolton.
The Latics took the lead through captain Gary Caldwell, who rose high to head in Jean Beausejour's corner.
McArthur spurned a chance to double Wigan's lead when he fired straight at Adam Bogdan from close range.
Mark Davies rifled in a half-volley to restore parity but McArthur atoned for his earlier miss to score the winner.
It may only be February but the game was must-win for two teams who are battling relegation and, as the Wigan players celebrated what could prove to be a pivotal win in their season at full-time, jeers rung out from disgruntled fans inside a Reebok Stadium.
But Bolton can have little complaints with the outcome, having been second best for long periods and only putting Wigan goalkeeper Ali Al-Habsi under significant pressure after the half-time introduction of Ryo Miyaichi - the Japanese youngster who was signed on loan from Arsenal in January.
Owen Coyle's side came flying out of the blocks and threatened Wigan from the start, with Caldwell almost turning into his own net after Martin Petrov's excellent delivery from the left caused panic.
Caldwell survived a handball claim moments later as Bolton started on the front foot.
But Wigan weathered the storm and grew into the contest, playing much of the first half as though their Premier League status depended on it.
Franco Di Santo, booked in the first half by Howard Webb for not allowing Bogdan to take a goal kick, was bright throughout and his low effort, turned around the post by Bogdan, led to the corner from which Wigan took the lead.
Escaping the attention of David Wheater, Caldwell found space in a packed penalty box to nod Wigan into the lead.
It was a lead the visitors richly deserved and threatened to add to in the second half, but McArthur was guilty of a bad miss that let Bolton off the hook.
Victor Moses made a driving run down the right before cutting back to McArthur who, only needing to put the ball either side of Bogdan, struck a tame effort straight at the goalkeeper.
And Bolton made McArthur pay for the miss, drawing level moments later with a classic route-one style goal.
A long punt forward by Bogdan deflected off the back of David Ngog and Mark Davies ran on to the loose ball and hammered it into the roof of the net on the half-volley.
The goal energised Bolton and, despite the boos directed at Coyle for replacing Chris Eagles with Miyaichi, the 19-year-old substitute added some much-welcome spark and creativity to Bolton's attacks.
But Wigan, who had gone nine league games without a win ahead of this fixture, absorbed the Bolton pressure and struck a winner that could prove a stepping stone to survival.
Getting ahead of Sam Ricketts, Moses burst forward into a shooting position. His shot was parried by Bogdan, but McArthur was on hand to tap in the loose ball to net the crucial winner.
Blackburn's victory over QPR added extra significance to Wigan's victory, who, instead of being cut adrift at the bottom of the league, have stayed in touch with their Lancashire rivals in the battle to avoid relegation, with two points now separating the bottom five clubs.