Danny Philliskirk's 12th goal of the season was enough to seal Latics a vital victory over Crawley Town at Boundary Park.
The striker stuck in the opening 20 minutes of the game to give Latics a four point cushion above the relegation places.
Latics started the game very brightly and had a few opportunities in the opening ten minutes of the game. James Wesolowski forced the goalkeeper into a one-handed save, whilst David Worrall tried his luck from 25 yards out which went wide of the goal.
Gary Harkins was causing a real nuisance and he twisted and turned only a couple of minutes later but was unfortunate not to get more than a corner.
All Latics' pressure payed off on 18 minutes as Danny Philliskirk fired them into the lead. Korey Smith drove into the box before feeding Wesolowski. He put it into the path of Philliskirk, who shimmied inside the area, and placed the ball past Paul Jones to make it 1-0.
With the rain lashing down over Boundary Park, the home side were oozing with confidence as they glided the ball around the surface, looking for more goals.
Latics were in the ascendancy and were unlucky not to extend their lead just five minutes before the break. Worrall stabbed a shot on the turn goalwards, but the ball just trickled past the post to the relief of Crawley Town's goalkeeper.
Only a minute later, Harkins drove at the defence and rifled a shot which the defender blocked. Clarke-Harris picked up the rebound, hit an effort on the angle, which the goalkeeper had to save with his feet.
Athletic started the second half as they finished the first. Clarke-Harris intercepted a loose ball in the Crawley back-line but his shot from the edge of the area just went wide of goal.
The visitors finally started to come back into the game as Billy Clarke forced Paul Rachubka into a smart save.
Substitute Jamie Proctor, minutes later, then found acres of space in the area but he could only direct his free header straight at the goalkeeper.
With the visitors pressing more and more, they were nearly caught on the counter attack with less than ten minutes remaining. James Dayton managed to deliver a ball into the box but somehow a Latics striker couldn't put the ball into the goal.
With five minutes of additional time announced, the home side kept possession in the Crawley Town half and saw out the game with relative comfort.
Oldham Athletic: Rachubka, Brown, Lockwood, Wilson, Grounds, Worrall (Dayton 67'), Wesolowski, Smith, Harkins, Philliskirk (MacDonald 78'), Clarke-Harris (Gafaiti 90')
Subs not used: Oxley, Dunfield, Millar, Winchester.
Crawley Town: Jones, Sadler, Connolly (Connolly 45'), McFadzean, Clarke (Fallon 80'), Drury, Simpson, Walsh, Kaikai (Proctor 45'), Tubbs, Jones.
Subs not used: Torres, Boateng, Maddison, Dicker.
Goals: Oldham Athletic (Philliskirk 18') 1-0 Crawley Town
Attendance: 3389 (81 visiting supporters)