Goals from former Spireites Kane Drummond and Mike Fondop did the damage in the first-half, with the dominant visitors deservedly in front.
The Blues made a triple change at the break but Drummond grabbed his second goal and Oldham’s third with less than 20 minutes remaining, which was the cue for many home fans to head for the exits.
Here are our player ratings from the game...
1. Zach Hemming 5
Zach Hemming 5 Started brightly, sweeping up, punching corners and parrying from Hammond. But he was soon picking the ball out of his net. Made a good save late on. Photo: Tina Jenner
2. Sam Curtis 4
Sam Curtis 4 Made a key intervention in the opening stages but seemed to be caught out of position too often. Spent a lot of the first-half sprinting back towards his own net. Taken off at the break. Photo: Tina Jenner
3. Chey Dunkley 4
Chey Dunkley 4 Back in the starting line-up, coming in for McFadzean, who then replaced him at half-time after a difficult 45 minutes. He had to be careful after being booked for dragging down Fondop after he got the wrong side of him. But it happened again from a goal kick and Fondop lifted the ball over Hemming for 0-2. Photo: Submitted
4. Sil Swinkels
Sil Swinkels A learning curve for the young centre-half. Struggled in possession as he was forced backwards often, although he deserved some sympathy because his options ahead of him were low quality. Mistakes crept in, including getting himself in a tangle for Oldham's third. Photo: Tina Jenner