Latics pick up their second away victory of the season as a Devarn Green strike in the first half saw off Chesterfield at the Technique Stadium.
Green got his first goal in a Latics shirt as he fired home from Ellis Chapman’s low cross to put Latics in front.
Chesterfield pushed for an equaliser, Ryan Colclough was dangerous down the left flank for the hosts, his teasing cross found Clements, but his headed effort went inches wide.
The Spireites pressed Latics in the second half, but in the end, they could find no way past Magnus Norman in the Latics goal, and the away side left with all three points.
Latics couldn’t have asked for a better start. Ellis Chapman ran down the left-hand side, he fired a cross into the box, Joe Nuttall couldn’t make a clean connection, but Green was on hand to fire home to give Latics the lead.
Chesterfield responded well, the lively Ryan Colclough should have levelled the tie 15 minutes later. He fired over from seven yards after Ollie Banks crossed from the right flank.
Just before the break, Liam Mandeville shot from the edge of the box, forcing a smart save from Norman, Ollie Banks was quickest to the rebound, but he couldn’t get the ball from under his feet and the Latics goalkeeper gathered.
After the break, Chesterfield continued to press. Bailey Clements fired a looping cross towards Paul McCallum, his headed effort was on target and heading towards goal, but Norman did well to tip behind for corner.
Latics then weathered the Spireites attacks well, not allowing the hosts to create many clear-cut openings.
John Rooney’s smart short corner found Ellis Chapman on the edge of the area, his strike was blocked by a wall of Chesterfield players and Ross Fitzsimons managed to claim.
Unsworth brought on Mike Fondop five minutes later, looking to give Latics a more attacking threat in the closing stages.
The striker made an instant impact, he shot on the volley following a quickly taken free kick, but his strike sailed over the bar.
Latics then managed the closing stages of the game well, the defence held firm and saw out the game, to pick up three points on the road.
Oldham Athletic: Norman, Hogan, Sheron, Shelton, Rooney (Clarke, 83), Green (Tollitt, 69), Kitching, Sutton, Chapman, Yarney, Nuttall (Fondop, 68).
Subs not used: Hudson, Reid
Attendance: 7,347 (1,306 Latics fans)