Alan Irvine's men took an undeserved lead through Billy Jones, but quickfire strikes from Anthony Stokes, his first for Palace, and Neil Danns handed the south Londoners their first win in five games.
Palace started much the brighter with Danns, Shefki Kuqi and Shaun Derry all missing decent opportunities for the home side to take an early lead.
But it was the visitors who edged in front completely against the run of play in the 29th minute when Palace were punished for falling asleep at a quickly taken throw-in leaving Jones to smash home from ten yards after Stephen Elliott's headed knock down.
But in a blistering four-minute spell, Palace dragged themselves in front, first through Stokes, who terrorised Callum Davidson down the right before spectacularly firing home past Andy Lonergan in the 32nd minute.
Then Danns tapped home from close range after Paul Ifill's cross just two minutes later completed a miraculous turnaround for the home side.
Former Millwall man Ifill sent a 20-yard daisy-cutter just wide seven minutes after the break, before Elliott sent an acrobatic bicycle kick straight at Julian Speroni as Preston searched for an equaliser.
Midfielder Danns went agonisingly close to extending Palace's lead late on but his header from John Oster's cross was tipped round the post by Lonergan.
Promotion-chasing Preston had a strong penalty shout for handball turned down in the dying minutes, but a point would have been more than the Lilywhites would have deserved as Palace comfortably held on for a morale-boosting three points.