Collins scored his second goal in two games as he slotted home Liam Mandeville’s cross to give the Shrimps another vital win.
Morecambe took the lead after only four minutes through Jordan Cranston. A swift Shrimps attack ended with Piero Mingoia crossing from the right-hand side and Cranston turned the ball past Daniel Iversen from eight yards out.
Oldham hit back and peppered the Shrimps’ goal with a string of crosses but Jim Bentley’s side always looked a threat on the break and created a number of chances to add to their lead.
Cranston forced Iversen into a flying save with a sweetly struck free-kick from 25 yards and the Oldham keeper reacted smartly again to tip away a diving header from Carlos Mendes-Gomes.
Mark Halstead then produced a fine save of his own to foil Jose Baxter’s close-range effort before blocking a long range effort from George Edmundson that took a deflection on its way to goal.
The second half saw Oldham again produce plenty of pressure but create no real chances until Baxter headed a left-wing cross past Halstead after 76 minutes to bring the home side back into the game.
The goal could have deflated the Shrimps but they hit back again and superb work from Mandeville found the space for Collins to score from close range.
Oldham: Iversen, Hunt, Edmundson, Clarke, Stott (rep Dearnley 50), Missilou, Sylla (rep Maouche 69), Branger, Nepomuceno, Baxter, O’Grady (rep Vera Mateos 72).Subs not used: De La Paz, Taylor, Coke, Robinson.
Morecambe: Halstead, Mills, Old, Sutton, Conlan, Mingoia, Mendes-Gomes (rep Mandeville 65), Kenyon, Cranston, Ellison (rep Oates 73), Bennett (rep Collins 73). Subs not used: Roche, Dalby, McKay, Hedley.
Ref: A Haines.