Peterborough saw their nine-match unbeaten run come to an end after Callum McManaman's late winner gave Wigan victory at the DW Stadium.
Wigan had led from the sixth minute when on-loan Fulham winger Martial Godo reacted quickest to Jordan Jones' cross from the left and prodded home.
After Callum Lang fired just wide, Jones then saw a 20-yard strike crash against the crossbar.
Peterborough were struggling to get anything going, with Harrison Burrows forcing a fine save from Sam Tickle.
The visitors stepped it up after the break, and levelled nine minutes after the restart when David Ajiboye's cross was drilled home by Kwame Poku.
Ajiboye came close to putting Posh ahead when he sent a left-footed strike whistling inches past the target.
Wigan made them pay when McManaman drilled home from the edge of the box with eight minutes remaining after Posh failed to clear a free-kick.
There was still time for Posh to threaten a leveller, only for Joel Randall to see a shot hacked off the line by Tom Pearce.
Match report supplied by PA Media.