Ipswich held off a spirited late fightback to end Wigan’s unbeaten home record and move up to seventh place in the Championship.
Midfielder Luke Hyam put Ipswich ahead when he finished Tyrone Mings’s excellent low cross from the left.
The points looked safe when former Latics player Conor Sammon doubled the lead as he scored from close range.
But Wigan responded as Martyn Waghorn turned in a James McClean shot and Oriol Riera thumped the post.
Riera was desperately unlucky not to level the score but for 75 minutes it was Mick McCarthy’s visitors who were in control.
Hyam had been involved in two tasty challenges in midfield when he put Ipswich ahead after a flowing move. David McGoldrick spread the ball out to Mings, and his superb delivery was met convincingly by Hyam to side-foot in.
Sammon – who scored once for Wigan during an 18-month spell at the club – should have made it 2-0 moments later when he failed to convert McGoldrick’s fine ball.
But after the break the powerful Irishman did grab his first goal for Ipswich since signing on loan from Derby County when he broke an unconvincing challenge from Ivan Ramis and slotted home at the second attempt after Scott Carson had saved.
Uwe Rosler’s home side belatedly rallied and Ramis forced Ipswich goalkeeper Dean Gerken into a fine stop before substitute Waghorn halved the deficit when he flicked in McClean’s shot from a corner.
And fellow replacement Riera was inches away from securing a point for the hosts when he showed superb technique to bring the ball down, before arrowing his shot against the near post.
The result leaves Wigan in 17th with eight points from eight games.