Talismanic striker Charlie Austin claimed his second career hat-trick as he powered Burnley to a morale-boosting first League win since the opening day of the season to leave poor Posh rooted to the foot of the table.
In a pulsating game which produced four goals in the first half and three in the final 20 minutes, the Clarets put their supporters, and doubtless manager Eddie Howe, through some anxious moments.
But in Austin they have a proven match-winner and the top scorer did it again just when it mattered.
Austin grabs his first and Burnley's second
With time beginning to run out and the sides locked at 2-2, Austin made the Clarets' barrage of chances count with a clinical finish and a successful penalty to add to a first-half goal which was helped over the line by defender Michael Bostwick but which will go down in his rapidly growing collection.
Junior Stanislas then capped things off to bookend an eventful afternoon which started with Chris McCann's early header and, despite replies from Lee Tomlin and Nathan Mendez-Laing which briefly gave Peterborough the lead, finished with the Clarets ending a three-game losing streak and heading back in the right direction.
With Martin Paterson restored to starting duty, the Clarets looked a far more potent force going forward and created more chances in the opening quarter of an hour than they had in the previous two games put together.
It was almost a case of target practice as the Peterborough goal resembled a coconut shy, Austin setting the ball rolling after just a couple of minutes when he rattled the crossbar from Paterson's lay-off.
And Peterborough's soft centre was quickly exposed again as McCann headed Burnley in front from an excellent Joseph Mills cross to the far post.
McCann heads the Clarets ahead
McCann, again, Austin, Paterson, twice, and Dean Marney all made the most of some wide open spaces to threaten a second goal.
But Burnley's own defence was far from watertight and in a disastrous three-minute spell all the good work at the other end of the pitch was undone as Peterborough struck twice to turn the game on its head.
The visitors had forced Lee Grant into two excellent saves in the opening five minutes through Tyrone Barnett and Shaun Brisley but even they must have been surprised to be in front.
Peterborough's first goal was handed to them when Michael Duff, starting his first Championship game of the season, up-ended Mendez-Laing and Tomlin converted from the penalty spot.
And the second was even more calamitous from a claret and blue point of view as the dangerous Mendez-Laing powered his way past Jason Shackell and Kieran Trippier before steering the ball beyond Grant.
It was crazy stuff and the action showed no sign of easing as Paterson almost sneaked a header past Bobby Olejnik and Mills produced an incredible goalline block to deny Mendez-Laing.
Burnley needed a goal before half-time, though, and it duly came six minutes before the break as Austin collected a pass from McCann and showed the Posh defence a clean pair of heels before beating Olejnik with an angled shot which was helped over the line by the despairing Bostwick.
Austin and Wallace celebrate the leveller
Having got level, the Clarets then almost went into the break back in front as a remarkable opening 45 minutes was summed up by Trippier's spectacular long-range which was top corner bound before Olejnik made a flying save to maintain the status quo and allow everyone to draw breath.
A pause was all it was, though, as within two minutes of the re-start Burnley had created another excellent chance as Mills delivered another fine cross which Austin headed just wide as he dived in beyond the far post.
Austin then created an opportunity for Paterson, charging down a clearance from Shaun Bisley which allowed his strike partner a run on goal stopped only by the outstretched leg of Olejnik.
But it wasn't all one way as Peterborough continued to look dangerous on the break as they strove to end a four-match losing start and Grant had to be watchful to drop onto an effort from Grant McCann as Barnett passed in front of him.
Barnett also spurned a great opportunity to slip in Mendez-Laing after Mills had been caught out but the Clarets were beginning to limit the flow and within minutes they struck at the other end to finally set up the victory.
McCann built on his early goal with an impressive performance and another driving run forward ended with a pass inside to Austin who did the rest.
Full of confidence, the striker took a touch, steadied himself and from 12 yards drove a shot into the top corner to make it half a dozen goals for the season.
Seven minutes later it quickly became seven and three much needed points for the Clarets as Austin picked himself up after being clattered by Olejnik to drive home the spot-kick to complete his 'treble'.
It was no more than Howe's men deserved for a scintillating attacking performance and they weren't quite finished as five minutes from time Stanislas helped himself to his first goal at Turf Moor, guiding the ball home after substitute Cameron Stewart had been denied by Olejnik's outstretched left hand.
Burnley: Grant, Trippier, Mills, Duff, Shackell, Marney, McCann, Wallace (Stewart 63), Austin (Stock 87), Paterson (Vokes 63), Stanislas. Subs: Mee, Edgar, Stock, Bartley, Jensen.
Booked: Mills 54
Peterborough: Olejnik, Alcock, Little (Ferdinand 84), Brisley (Zakuani 60), Bostwick, Tomlin, McCann, Frecklington, Barnett, Boyd (Sinclair 69), Mendez-Laing. Subs: Newell, Knight-Percival, Clarke-Harris, Day.
Booked: Olejnik 81
Referee: Mike Dean