For 80 minutes it looked as though it was going to be a frustrating day for Palace. Having peppered the Peterborough goal throughout they found themselves a goal behind, but two goals in two minutes from Andre Moritz and Kagisho Dikgacoi earned the Eagles the 2-1 win their performance deserved as they returned to the top of the Championship.
Palace were unchanged from the side that thrashed Ipswich in midweek, but after a sluggish start they found themselves a goal down after six minutes when George Boyd's attempted shot deflected into the path of Grant McCann who slotted the ball past the wrong-footed Julian Speroni.
Following the early setback, the Eagles began to create chances and Peter Ramage headed narrowly past the post from an Owen Garvan cross before Wilfried Zaha cut onto his left foot and forced Bobby Olejnik to tip the ball over his bar with a rasping shot.
Despite the visitors controlling possession and territory, it was Posh who were carving out the best chances and should have been two goals ahead on 22 minutes when Craig Alcock connected with a McCann corner but headed wide, and later Speroni could only keep out Michael Bostwick's long-range shot via his chest.
Seven minutes before the interval a snap shot by Boyd missed the target by inches and Yannick Bolasie dragged a shot wide on the half-time whistle as the Eagles headed into the changing rooms a goal down despite looking threatening throughout the opening 45 minutes.
In the second half Palace began to create better opportunities. Glenn Murray and Zaha forced the inspired Olejnik into two smart saves, Murray saw a downward header bounce over the bar, Damien Delaney fired over from a corner and Zaha beat four defenders before shooting just wide of the far post in the opening 20 minutes.
Just as it looked like the breakthrough would never come, 10 minutes from time two substitutes combined as Aaron Wibraham played in Moritz who burst into the box and smashed the ball into the bottom corner off the post to equalise.
And the turnaround was complete two minutes later when the Eagles opened up a three on two counter attack and Zaha squared the ball to Dikgacoi who put the ball in the same place as Moritz to send the 3,500 travelling fans behind the goal into bedlam.
Even with the lead theirs, Ian Holloway's side continued to attempt to seal the win and only some goalkeeping heroics from Olejnik prevented Murray and Zaha adding a third but ultimately two was enough to secure their first ever win at London Road and send Palace back to the Championship summit.
Peterborough: Olejnik, Alcock, Brisley, Bostwick, Tomlin (Swanson 63), Boyd, McCann, Newell, Little (Ferdinand 84), Knight-Percival, Berahino (Barnett 67). Subs: Day, Zakuani, Sinclair, Mendez-Laing.
Palace: Speroni, Ward (Wilbraham 80), Parr, Bolasie (Blake 84), Dikgacoi, Garvan (Moritz 74), Jedinak, Zaha, Murray, Delaney, Ramage. Subs: Price, Easter, Moxey, O'Keefe.