Kemar Roofe had rifled United into a 13th-minute lead after excellent work from Kalvin Phillips and Leeds impressed in continually pouring forward in the first half.
But they hit the self-destruct button after the break with Paul Gallagher netting a 49th-minute equaliser from the penalty spot after Vurnon Anita had fouled Billy Bodin.
Sean Maguire then nodded home Gallagher’s cross just three minutes later as United’s Pontus Jansson injured himself in his attempts to clear.
Another miserable night for the badly-faltering Whites was then sealed when Preston bagged a third goal six minutes from time through Alan Browne to maintain North End’s outside chances of reaching the play-offs.
Leeds went to Deepdale following a rotten return of just 12 points from their previous 17 games – an unwanted record only equalled by bottom Burton Albion. The Whites have won just twice since the 2-1 triumph at Burton on Boxing Day with head coach Paul Heckingbottom now looking at a return of ten points from his first 12 games.
He was missing ten men last night with suspended Gaetano Berardi joining nine injured players on the sidelines.
Even so, Heckingbottom’s team selection raised a few eyebrows with Dutch striker Jay-Roy Grot handed a full league debut with top scorer Pierre-Michel Lasogga benched and Spanish playmaker Samu Saiz among those to drop to a substitute’s role.
But United took the lead in the 13th minute when a Pablo Hernandez corner was cleared to Phillips, who darted into the area before rifling in a low cross that Roofe hammered into the roof of the net from close range.
Preston looked to respond immediately and Sean Maguire should have done better with two free headers from corners that were sent over and wide.
United, though, were causing North End plenty of problems and Hernandez and Caleb Ekuban both went close before Preston clipped the outside of a post through a curling effort from Bodin.
But Leeds were on top and the Whites ended the half by twice going close to doubling their lead with Ekuban forcing a fine save from Declan Rudd before Roofe narrowly failed to beat the Preston goalkeeper to a Hernandez cross. United were good value for their 1-0 lead at the break, but Preston were handed a golden opportunity to equalise just four minutes after the interval when Anita sent Bodin tumbling in the penalty box.
Referee Lee Probert immediately pointed to the spot and Gallagher stepped up to hammer home the penalty into the bottom right corner.
North End suddenly had their tails up and Peacock-Farrell tipped a goalbound drive from Browne over the bar.
From the resulting corner, Gallagher’s delivery was seized upon by Maguire who this time made no mistake with his free header, which soared past Peacock-Farrell.
United centre-back Jansson injured himself in trying to clear the cross and the Swedish international had to be substituted by Academy centre-back Hugo Diaz, who had raised eyebrows as it was by appearing on the bench.
Peacock-Farrell turned behind a rising shot from Greg Cunningham as Preston went in search of a third before United’s first attempt of the half from Ekuban was deflected over the bar. Heckingbottom then called for Saiz and Gjanni Alioski as part of a double change with 22 minutes left.
Hernandez went close when drawing a fine save from Rudd in the 77th minute before the Lilywhites’ goalkeeper beat away a long-range drive from Anita.
But United’s patched-up defence always looked vulnerable and so it proved with North End adding a third goal eight minutes from time when Browne powered home a header from Callum Robinson’s cross.
Preston North End: Rudd, Clarke, Huntington, Davies, Cunningham, Pearson, Gallagher (Harrop 67), Bodin (Horgan 84), Browne, Barkhuizen (Robinson 76) , Maguire. Unused substitutes: Maxwell, Woods, Moult, Earl.
Leeds United: Peacock-Farrell, Anita, Jansson (Diaz 57), O’Connor, Dallas, Vieira, Phillips, Hernandez, Roofe (Saiz 68), Ekuban, Grot (Alioski 68). Unused substitutes: Lonergan, Pearce, Nicell, Lasogga.
Referee: Lee Probert (Wiltshire).