The goal came early in the second half after a superb flowing move which the Burton Albion loanee finished off confidently.
That result lifted Latics above their relegation rivals and put them within sight of Doncaster Rovers who occupy 20th position.
Manager John Sheridan made a couple of changes to his starting line up from Saturday’s game as Curtis Main’s impressive second half display earned him a starting place.
It was a first half that lacked real chances on goal but it would be Latics who went close first.
After a corner was cleared, it fell to the path of Anthony Gerrard but he volleyed over the crossbar.
It was Latics that were doing the early running and Main’s shot on 11 minutes was stopped by the hand of Blackpool defender Tom Aldred but the referee decided it not worthy of a free kick.
In difficult conditions, the game struggled to get going but David Norris hit a strike in anger on 17 minutes which flashed wide of Joel Coleman’s goal.
Midway through the half, the ball fell invitingly for Matt Palmer on the edge of the box but the Burton Albion loanee fired straight at the goalkeeper.
Minutes later, Jonathan Forte battled for the ball after Mike Jones crossed into the box but he effort was blocked for a corner.
Both sides were struggling to keep hold of possession in what was turning to be a disappointing first half for both teams.
Brian Wilson and Aaron Amadi-Holloway were limited to half chances as it ended goalless at half time.
Both teams seemed to receive a strong word at half time as it was a bright start to the second half.
David Norris struck wide two minutes into the half whilst minutes later Brad Potts tested the palms of Coleman.
Latics broke forward and a pass released Curtis Main through on goal but Blackpool goalkeeper Colin Doyle saved well to his right.
Two minutes later, Latics took the lead through a superb passing move finished off by Palmer.
A move consisting of a number of passes was laid into the path of the Burton loanee and he smashed into the top corner from 10 yards to give Latics the valuable lead.
That move lifted the supporters as the game started to boil over.
Both Liam Kelly and Potts were booked for an altercation and then two minutes later, Jones found himself in the referee’s notebook for an off-the-ball incident.
With Latics going in search of another goal, they almost got it through a deft Forte header.
Brian Wilson’s cross from the right found the forward in the centre and his backwards header fell the wrong side of the post.
Holloway was putting himself about in attack and causing a nuisance for the Blackpool defenders.
The fans were doing their upmost to lift the players in the final minutes as the game started to become tense.
With balls flying in and around Coleman’s box, substitute Carl Winchester hammered clear and the referee blew his whistle to signal a huge win for Latics.
Oldham Athletic: Coleman, J.Wilson, Gerrard, Dieng, B.Wilson, Kelly, Jones, Palmer, Forte (Thiele 79’), Holloway (Winchester 89’), Main.
Subs not used: Cornell, Brown, Mills, Croft, Tuohy.
Blackpool: Doyle, White, McAlister (Osayi-Samuel 74’), Jones, Potts, Aldred, Philliskirk (Paterson 80’), Norris, Smith (Yeates 54’), Higham, Ikpeazu.
Subs not used: Cullen, Redshaw, Boyce, Lyness.
Goals: Oldham Athletic (Palmer 53’) 1-0 Blackpool
Attendance: 3,715 (338 visiting supporters)