Conor Wilkinson’s low drive after linking with Danny Philliskirk after 74 minutes proved to be the game’s only goal, helping Oldham end a three-match losing streak.
Crewe have lost five of their last six and, just two points off the relegation zone, are mired in a battle for their League One survival as Oldham seek to pull clear of the lower part of the table.
Goals from Dean Bowditch, Daniel Powell, and Ben Reeves gave MK Dons a winning lead before Rhys Turner’s late strike offered scant consolation for a poor Oldham on Tuesday.
Former Oldham Athletic manager Lee Johnson came back to haunt his old side as Barnsley brushed aside the 10-man Latics 3-1.
Oldham Athletic interim manager Dean Holden has warned his players not to get too ‘emotionally involved’ when they face former boss Lee Johnson’s new side Barnsley on Saturday.
Carl Winchester had put Oldham ahead on the stroke of half-time, but Joel Grant’s equaliser ten minutes after the break and Hayter’s late winner mean Oldham have now lost four of the last five.
The former Oldham Athletic captain took temporary charge at the League One side when ex-manager Lee Johnson left for Barnsley last month.
Two Preston goals in each half, including a first half-strike from ex-Latics loanee Daniel Johnson, settled the game 4-0 as Oldham lost their third straight match.
Lee Johnson left Oldham in ninth place in League One and just two points off the play-off places, and former Latics captain Dean Holden is setting his sights on promotion to the championship.
The 33-year-old leaves Oldham in ninth, seven places above his new club, whom he saw beat Scunthorpe 1-0 on Tuesday night.