A first-half goal from Wimbledon's Ben Chorley put a severe dent in Wigan's play-off hopes and earned his side a stay of relegation execution.
Had the Dons lost at the JJB Stadium they would have been officially playing second division football next season, and while this victory only delays the inevitable it will certainly cause no end of problems for Wigan at the other end of the table.
Wigan's poorest display of the season set the pattern for this coupon-busting result and stand-in keeper Gary Walsh must take the blame for the Dons' fifth minute winner.
Walsh completely misjudged Jason Puncheon's in-swinging corner and Chorley got the deftest of flicks at the near post.
Even then it seemed only a matter of time before the home side got back on level terms and powered on to victory, but the expected onslaught never came.
A disjointed Latics display saw few chances created and the normally lethal strike force of Jason Roberts and Nathan Ellington simply never kicked into gear.
Ellington probably had Wigan's best chance when he blasted over from six yards and then saw Wimbledon keeper Scott Bevan produce a goal-line save from his powerful header.
Andy Liddell volleyed over, skipper Jason De Vos saw Bevan kick his close-range header over the bar and midfielder Jason Jarrett volleyed wide.
But it was Wimbledon who had the best chance to seal the game in a rare break when Shola Oyedele played a one-two with Wayne Gray and saw his shot clip the bottom of the post with Walsh a spectator.