Former Latics loanee Freddie Ladapo headed the only goal of the game on 68 minutes to seal Shrewsbury Town the victory.
He thought he had opened the scoring in the first half but the referee and linesman combined to rule out his goal for offside.
Manager John Sheridan gave debuts to two of his new signings with Anthony Gerrard returning for his third spell with the club against his former side and Michael Ngoo lead the line in a 4-4-2 formation.
It would be the visitors who started the better of the two sides with Joe Riley and Shaun Whalley going close early on.
However, it did not take Latics long to find their feet with Ryan Flynn taking the game to the home side.
His first shot was blocked on eight minutes whilst the same again happened on 11 minutes as his effort from 18 yards was blocked by Aristote Nsiala.
Ngoo, on his debut, was putting himself about in attack whilst a shot from Brian Wilson a minute later went wide of Jayson Leutwiler’s goal.
Latics had to be wary midway through the half as Tyler Roberts was played through on goal by Ladapo but Gerrard stuck his leg out to win the ball and clear the danger.
Whilst Ousmane Fane received a booking minutes later, Josh Law, who netted the only goal of the game against Gillingham last week, struck a free kick over the crossbar just before the half hour mark.
Shrewsbury Town thought they had taken the lead on 31 minutes as Ladapo converted from close range.
After the celebrations calmed down, the referee consulted with his linesman and the pair came to the decision to disallowed the goal for what looked to be offside.
The home side looked to capitalise on the decision and took the game to Latics. Gary Deegan saw a shot flash wide before Peter Clarke was booked for a foul on Alex Rodman.
Before the break, Whalley fired over for the hosts, and half time probably came at a good time for Latics.
Straight after the break, Ngoo had a great chance to give Athletic the lead but his outstretched leg could not convert Brian Wilson’s deep cross.
It was worrying signs soon after as Cameron Dummigan had to be stretchered off following a coming together with Connor Ripley.
Ollie Banks was brought into the action to replace the full back, and also Aaron Amadi-Hlloway replaced Ngoo.
And Holloway almost set up the opening goal for Latics on the hour mark.
Ryan McLaughlin got to the byline, crossed into the centre for Holloway, he headed into the path of Mckay but his overhead kick fell wide of the far post.
The home side did take the lead on 68 minutes through Ladapo.
After a cross into the box was not cleared, the ball sat up for Ladapo to head home from three yards and give the Shrews the lead.
Latics were struggling to get hold of the ball in attack and were being met by a stubborn Shrewsbury Town defence.
Sheridan’s could not work a clear cut goalscoring opportunity with Holloway trying his best in attack to make something happen.
In injury time, Banks nodded into the centre of the box but nobody could get onto the end of his ball in as Latics fell to defeat at the Greenhous Meadow.
Shrewsbury Town: Leutwiler, Riley, Sadler, Whalley (Morris 88’), Ogogo, Brown, Deegan, Ladapo, Nsiala, Rodman, Roberts (El-Abd 77’).
Subs not used: Halstead, Grimmer, Smith, Anderson, Barnett.
Oldham Athletic: Ripley, Dummigan (Banks 58’), Gerrard, Clarke, Wilson, Fane, Law, McLaughlin, Flynn, Mckay (Erwin 71’), Ngoo (Holloway 57’).
Subs not used: Kettings, Reckord, Edmundson, Green.
Goals: Shrewsbury Town (Ladapo 68’) 1-0 Oldham Athletic
Attendance: 5,537 (739 visiting supporters)