Matthew Lund’s first half strike was enough to seal the three points for Dale in a tough afternoon for Oldham Athletic.
Manager Stephen Robinson made one change to his side from last weekend’s defeat against Bristol Rovers as Ryan McLaughlin replaced Carl Winchester.
It was a slow start to the game with both sides enjoying good spells of possession.
After Connor Ripley held onto a deflected Nathaniel Mendez-Laing effort, Latics almost went in front a minute later as Paul Green’s cross found Freddie Ladapo but he could not connect properly with his volley.
Mendez-Laing caused Latics early problems as on 13 minutes he danced past three Latics players but captain Peter Clarke stood up well and took the ball away from the winger.
Athletic did have the ball in the back of the net midway through the first half but Clarke was adjudged to be offside from a free kick into the box.
Minutes later, the home side almost took the lead as Joe Bunney’s free kick was destined for the top corner but Ripley managed to tip the ball onto the crossbar and it was cleared.
Latics were struggling to hold the ball up in attack as Rochdale started to take a grip of the game.
However Latics had their first real shot of the game on 35 minutes as Lee Erwin created space for himself on the edge of the box but goalkeeper Josh Lillis saved well.
Five minutes later, Cameron Burgess had to throw his body on the line as Steven Davies chested down for Lund six yards out but the defender managed to get a body part to the ball to clear.
However, a minute later, the same player would make Latics pay as he put Rochdale one goal ahead.
Calvin Andrew had space on the left and his low cross found Lund and he fired into the far corner to give Dale the advantage.
Latics responded well to going a goal behind and forced two good chances to get back on level terms.
Firstly Ladapo was released in the penalty box and he forced a smart save from Lillis whilst a minute later, Clarke met a Green free kick into the box but his header was again saved by Lillis.
Robinson made a change at half time as Billy Mckay replaced Ladapo and Latics started the second half brightly.
All the danger was coming down the right hand side with Cameron Dummigan and McLaughlin causing problems.
Cross after cross was going into the box from the pair but unfortunately not falling onto an Oldham Athletic head.
However, Latics were full of momentum and they were backed by the healthy crowd which made the short trip over.
On 55 minutes, Latics maybe should have levelled through Mckay as Green found the striker at the front post but his header went over the crossbar.
For all their dominance, they had to be wary of the break and they were almost made to pay on 57 minutes as Mendez-Laing got behind the defence but Ripley saved.
Latics raced up the other end and almost found the equaliser through Erwin as he aimed for the top corner but it was just offside.
Latics continued to press Rochdale in a bid to get something out of the game and with only 20 minutes remaining, Erwin almost found a stunning leveller.
The striker turned 35 yards from goal, and hit a sweet volley which was destined for the top corner but it went inches wide.
Athletic had to be aware defensively with Callum Camps forcing a good save from Ripley whilst two minutes later, Clarke was forced into last ditch defending as he denied Joe Thompson.
Erwin had a golden opportunity to equalise with only five minutes of the game remaining as he turned three men in the area but his tame shot was saved.
Latics continued until the end but were unable to grab an equaliser as they fell to a defeat on derby day.
Rochdale: Lillis, Rafferty, Canavan, Lund, Andrew, Camps, Mendez-Laing (Thompson 68’), Keane, Davies (Odelusi 88’), Cannon (Rathbone 71’), Bunney.
Subs not used: Logan, McNulty, McDermott, Morley.
Oldham Athletic: Ripley, Dummigan, Clarke, Burgess, Reckord, McLaughlin, Fane (Jahraldo 90), Green (Winchester 73’), Flynn, Erwin, Ladapo (Mckay 46’).
Subs not used: Kettings, Wilson, Banks, Osei.
Goals: Rochdale (Lund 41’) 1-0 Oldham Athletic