The 5-0 mauling at Edgar Street has been John Sheridan's worst result in management, but his Latics team got their promotion bid back on track with goals from Danny Whitaker, Lee Hughes and Chris Taylor.
Oldham could have been out of sight at the break as they made a catalogue of chances, but found Hatters keeper Owain Fon Williams in defiant mood.
The visitors threatened a comeback from 2-0 down, but Taylor's strike in the second half condemned them to a rare away loss.
Stockport almost broke through in the first minute when Leon McSweeney saw his shot cleared off the line by Scott Golbourne, making his debut on loan from Reading.
After that it was one-way traffic for half an hour and Oldham took an early lead when County failed to clear a Dean Windass cross and Whitaker drove the loose ball into the bottom corner from 20 yards.
Windass headed off target before Fon Williams made alert saves from Hughes and lively winger Deane Smalley.
Oldham's lead doubled after 18 minutes when Windass flicked on and Hughes made progress into the box, before converting his 15th goal of the season from eight yards.
Stockport had posed few questions going forward, but they pulled a goal back before the break when Johnny Mullins crossed and young substitute Oli Johnson guided in a close-range header.
Oldham came under pressure early in the second half, but their nerves were settled after Windass showed his quality in the build-up.
Windass, on loan from Premier League Hull, sent Taylor charging through the visitors' defence and the highly-rated winger side-footed past stranded keeper Fon Williams from 12 yards.
Taylor could have increased Oldham's advantage, but he was thwarted by two fine saves from Fon Williams as the home side cruised to victory.