Tyreeq Bakinson stuck midway through the second half to condemn Latics to their second league defeat of the season.
Latics dominated the contest, but the ball would just not go in the back of the visitor’s net as a run of five league games unbeaten comes to an end.
The game had the feel of a tight affair as neither team could create anything worthy of note in the opening exchanges.
However, Newport defender Fraser Franks may have considered himself lucky after a high challenge on Callum Lang was deemed only a yellow card by referee Mark Heywood.
Andy Taylor down the left-hand side was causing problems with his pinpoint crosses, but evading teammates by inches on several occasions.
Sam Surridge and Franks then tangled in the box from a Latics corner and Surridge seemed to gesture he was stamped on in the aftermath, but nothing was given.
Newport grew into the game and Zeus De La Paz had to be at his best with two fantastic saves in a matter of minutes.
Dan Butler’s cross wasn’t dealt with by Oldham and Josh Sheehan found himself with space to shoot, but De La Paz was there to save.
The Curacao’s next save was even better as Franks found himself free inside the Latics box and his effort was arrowing into the top corner, but De La Paz somehow managed to tip it over the bar.
The home side responded well as Surridge almost found his strike partner Chris O’Grady, but the teasing ball just evaded him and the goal.
Dan Gardner skipped his way past the Newport defence forcing Joe Day into a smart stop as the teams went in at half time locked at 0-0.
De La Paz had work to do early in the second half as he tipped over a Jamille Matt header before Lang danced his way into the box to release Surridge, but his shot come cross evaded everyone and the goal post.
Johan Branger-Engone headed straight at Day from a Taylor cross as Newport soaked up the home sides pressure before getting themselves ahead.
Butler played a long ball into Bakinson who spun and finished smartly past De La Paz into the far corner of the goal.
Jose Baxter was introduced, and he almost found a goal with his head, but he could only guide it over the bar.
Keanu Marsh-Brown could have sealed the game after nicking it off Clarke and De La Paz, but his touch let him down on this occasion.
Branger-Engone should have put Latics level after yet another Taylor cross from the left found the Gabonese winger, but he headed over the bar.
Latics continued to push, but to no avail and Frankie Bunn’s men will be looking to respond next week at Grimsby Town.
Attendance 4239 (259 Away)
De La Paz, Hunt, Clarke ©, Edmundson, Taylor, Lang, Missilou (Maouche 88’), Gardner, Branger-Engone (Benteke 90’), O’Grady (Baxter 74’), Surridge
Newport County AFC
Day, Pipe, Butler, Franks, Dolan, Amond, Matt (Marsh-Brown 74’), Bakinson, Sheehan (O’Brien 84’), Bennett, Demetriou ©