Duane Holmes grabbed a late winner as Scunthorpe edged an end-to-end battle 3-2 at Oldham.
The Iron substitute converted from close range in the 83rd minute, shortly after ex-Scunthorpe striker Craig Davies appeared to have rescued a point for the hosts in what was the first defeat of Oldham manager Richie Wellens' eight-match reign.
Tom Hopper netted in the fifth minute as Oldham goalkeeper Jack Ruddy could only push Lee Novak's shot into his path.
Five minutes later, the lead was doubled when Josh Morris was slipped in down the left side of the area to slot calmly across Ruddy.
Home skipper Peter Clarke reduced the arrears shortly before half-time with a close-range header, meeting Kean Bryan's nod-back.
Hopper had claims for a penalty turned down when he went over under a challenge from Ruddy inside the box.
Davies crashed home to make it 2-2 after a free-kick was not cleared with Aaron Amadi-Holloway sending a header towards the far post into his path.
But Holmes had the final say, converting a Morris cross from close range to make it back-to-back wins for the visitors.