An unbelievable comeback from Latics saw them clinch a 5-4 win against all the odds as centre half Genserix Kusunga slammed home an added time winner.
The Latics looked a beaten side as they trudged off at the break trailing by three goals, but with midfielder Gary Harkins the mastermind for Lee Johnson's side in the second period they launched an incredible comeback to take the points. The scot grabbing his first two goals for the club to rightly clinch the sponsors 'man of the match' award.
A relieved Lee Johnson said afterwards: "At half time there were a few serious home truths told in the dressing room, but I have to say fair play to the lads as they put it right themselves. The character they showed, and in particular those who got us going in the second half, was superb"
The manager added: "We should have taken the lead in the first minute, but then conceded poor goals to make it hard for ourselves. They kept killing us on the break, we gave the ball away in good areas and with men committed forward, we were left exposed to their counter attacking game, which we couldn't deal with in the first half".
Johnson had named an attacking line-up for the game against Posh at Boundary Park, with Korey Smith moving to right back allowing David Worrall to take his place in the starting line-up for the first time since his arrival on loan from Rotherham United.
Latics should have taken the lead as early as the first minute as Charlie MacDonald blazed well over after Gary Harkins had ridden three challenges before playing in a neat pass to MacDonald.
Worrall was soon in the thick of the action, his cross a minute later diverted for the first corner of the match. Posh clearing the ball in from James Dayton with ease.
GOAL 0-1 - After being pegged back in their own half for the opening five minutes, Posh took the lead in their first foray forward. Top scorer Britt Assombalonga heading home a delightful cross from Nicky Ajose, who had found space on the right.
Harkins again caused the visitors defence problems with another mazy run on 12 minutes, his right foot effort from the edge of the box blocked Nat Knight-Percival, the loose ball falling behind MacDonald.
Another swift counter from Posh almost gave them a two goal lead. Another break down the right by Ajose saw him feed Danny Swanson, with only a superb block from Kusunga stopping his neat side foot effort finding the net.
Latics were still pushing forward at every opportunity, Harkins finding space for those around him, but the visitors were looking dangerous with their swift counter attacks. Swanson wasting a great chance on 22 minutes after Lee Tomlin had created the chance with a neat turn and cross on the left.
GOAL 0-2 - Posh skipper Tommy Rowe rose unchallenged to head home from the visitors second corner kick of the game. Latics complaints that Worrall had been fouled in the build-up falling on deaf ears.
James Dayton then saw an effort charged down, his drive from the left side of the box, after Smith's diagonal free kick, being blocked in the six yard box.
Assombalonga was lucky to escape a yellow card on the half hour, his late lunge on Mark Oxley going unpunished by referee Clark.
With ten minutes to play before the break, Johnson made a double substitution, Jonson Clarke-Harris and Connor Brown replacing Danny Philliskirk and James Dayton. Brown dropping in at right back with Smith returning to his customary midfield role.
The substitutions lifted the team immediately as Latics forced two corners in quick succession, but yet again Posh caught them out with another counter attack, Oxley forced to tip Tomlin's effort over for a corner kick.
GOAL 0-3 - It became a real struggle for Latics right on half time as Tomlin took advantage of hesitancy in the home sides backline to slot home.
Latics left the pitch at the half-time whistle to a chorus of boos from their supporters, with several heading for the exit, seemingly no way back for their team.
HT: Latics 0 Peterborough United 3
Whatever was said in the dressing room at the break certainly worked as a different Latics side started the second half in confident mood and within minutes they had a foothold in the match.
GOAL 1-3 - Brown was brought down on the edge of the visitors box after a terrific run had taken him through three challenges. Harkins free kick being superbly tipped away for a corner by Joe Day. Harkins however wasn't to be denied his first goal for Latics as he swept home a loose ball following Smith's corner kick.
GOAL 2-3 - The fight back continued as Worrall grabbed his first goal for the club just six minutes later. Harkins being the architect with a brilliant piece of skill to leave Mark Little in his wake, before laying on a neat pass for Worrall to smash home passed Day.
With the Boundary Park crowd now fully behind them, Latics were first to every ball and they were soon on their feet again as a long range effort from Brown whistled just wide.
Clarke-Harris appealed for a penalty on the hour mark, his run into the box brought an end by a combination of Michael Bostwick and Craig Alcock, referee Clark waving away his protest.
GOAL 2-4 - The game took another turn away from Latics on 62 minutes, Ajose the beneficiary following a defensive mix up. Jonathan Grounds throw-in was left by both Oxley and Kusunga, the winger slotting home to put his side two goals clear again.
GOAL 3-4 - Latics were back in the game five minutes later and again it was Harkins who created the chance. Again he showed great skill to get down the left hand side, cutting inside the box before laying the ball into the path of Grounds to cross for James Wesolowski to prod home under Day, bringing the Boundary Park crowd to their feet again.
Within minutes Harkins created another chance, Day superbly saving to stop Worrall doubling his tally from the Scots deep cross.
Latics were now well on top, Harkins deft lob from the edge of the box then almost bringing the scores level, before Worrall's effort from the edge of the box was charged down in the six yard box by a desperate Posh rearguard.
Posh who, were being kept in their own half by the resurgent Latics, showed they were still a danger on the break as Rowe tested Oxley from long range on 85 minutes. The Latics keeper dealing with the shot comfortably.
The game then took yet another turn as Latics were awarded a penalty on 86 minutes after Tomlin dived to save James Tarkowski's header off the line. Referee Clark sending the midfielder off for handball.
GOAL 4-4 - Harkins claimed his second goal for the club, slamming home the resultant spot kick to bring Latics level.
The mood at Boundary Park was that Latics could actually win this game, and with The Chaddy End on its feet Latics earned yet another corner kick in the last minute of added time.
GOAL 5-4 - Unbelievably Latics completed the comeback to end all comebacks as centre half Kusunga smashed home James Tarkowski's knockdown from Harkins' corner to give his side a win that looked to be impossible for long periods of an enthralling match.
Such were the celebrations after the goal that Kusunga and Brown went into referee Clark's notebook, the goal scorer for jumping into the crowd, the defender for kissing the referee!!
FT: Latics 5 (Harkins 2, Worrall, Wesolowski, Kusunga) Peterborough United 4
Johnson was clearly happy with his players second half performance after the match: "We have gone through every emotion, from rock bottom at half-time, when we had some harsh words, to come out and play like that, it goes to show that they care about this club and me as a manager
"It was a big win for us, especially with other teams losing. From being dominated in the first half we have dominated a top side, scoring five goals in a half. I have kept saying to the lads that they have that type of performance in them. We have a lot of quality in that dressing room and if they play with type of intensity, passion, running, passing and willpower they will prove what a good side they can be".
Harkins adding: "It was nice to get a couple of goals and a couple of assists, it helps repay the gaffer for believing in me and bringing me to the club. I didn't feel any pressure taking the penalty to bring the scores level, I was confident that I would score"
ATT: 3,571 (273)
Latics: Oxley, Grounds, Wesolowski, Kusunga, Tarkowski, Smith, MacDonald, Dayton (Brown), Philliskirk (Clarke-Harris), Worrall, Harkins.
Unused Subs: Rachubka, Mellor, Winchester, Rodgers, Lockwood.
Possession - 51%
Shots on Target - 18
Shots off target - 7
Corners - 9
Fouls - 5
Bookings - 2 (Kusunga, Brown)