League leaders Chesterfield departed Boundary Park with all three points as two early goals proved critical.
A goalkeeping error led to the opener inside the first minute and was followed up with a second goal after eight minutes.
There was no way back for Latics, who featured two debutants in Manchester United’s Charlie Wellens – son of Richie – and David Okagbue from Stoke City. Both did well, with Okagbue being named man of the match.
The hosts did carve out some opportunities, most notably via Hallam Hope, but there was no way through against a Spireites side who are yet to taste defeat this season.
The hosts were up against it from the off as with only a minute on the clock Magnus Norman couldn’t clear his lines and Joe Quigley nicked the ball away from the keeper before steering a shot into the corner of the goal.
And things got worse for the hosts soon afterwards – Quigley’s shot was blocked, but the ball came back into space for Jeff King to convert.
It looked a tough road back for Latics against the league leaders, but there was a response with a flurry of corners, a deflected Dan Gardner drive and a clever lob from Hope which landed on the roof of the net.
Mike Fondop also headed off target before Latics were dealt a further blow as captain Gardner hobbled off injured.
Good approach play from Latics resulted in Ben Tollitt blasting into the side netting, but it was Chesterfield who had the best chance of the remainder of the first half as Branden Horton blasted a drive against the base of Norman’s right-hand post from an acute angle.
The Latics keeper saved at close range from Quigley in the early stages of the second half – the Spireites striker receiving the ball in space despite looking offside.
Quigley should have finished it with 25 minutes to play, cutting in off the right but blasting his shot wide when in a good position.
And Ollie Banks twice fired wide against his former club in the latter stages as the visitors closed out the victory.
Latics: Norman, Wellens (Burgess, 61) Coop, Roberts, Clarke, Okagbue, Sheron, Gardner (C) (Cooper, 32), Threlkeld, Tollitt, Hope, Fondop (Luamba, 60).
Subs Not Used: Leutwiler, Stobbs.
Chesterfield: Covolan, King, Horton, Williams, Grimes (C), Mandeville, Clarke (Akinola, 65), Banks, Miller (Uchegbulam, 60), Oldaker (Gyasi, 83), Quigley.
Subs Not Used: Maguire, Jones.
Attendance: 7,852 (1,469 away)