But defeat for Preston keeps them in deep trouble as they languish in the bottom two.
A poor first half was lit up by a three-goal flurry in the final ten minutes. Julian Speroni had already made a fine save to stop Callum Davidson from scoring on 34 minutes, but he had no chance stopping Youl Mawene's far-post header from Darren Carter's corner three minutes later.
Palace replied quickly after Speroni's long clearance was headed on by James Scowcroft for Clinton Morrison to cleverly hook the ball over Andy Lonergan in the Preston goal to put the Eagles back on terms.
And to finish the first period, Ben Watson's free- kick fell nicely to Morrison who was left with only Lonergan to beat.
He fired straight at the Preston custodian but luckily for Palace Clint Hill was on the edge of the box with a looping header that dropped just under the crossbar to give Palace a 2-1 half-time lead.
After the break Palace played with more conviction, Tom Soares and Watson prompting and probing in midfield. The latter laid on a low cross which Sean St. Ledger somehow cleared away from under his own crossbar and John Halls, a minute later, cleared Watson's corner at the far post.
Palace continued to push forward and Watson's volley forced Lonergan into a fine refelx save.
Although Alan Irvine's Preston were defending in numbers they nonetheless had a couple of useful chances. In the last 15 minutes Patrick Agyemang shot straight at Speroni and shortly afterwards substitute Andy Carroll saw his header deflected away for a corner.
Preston piled players forward in the dying minutes, but their enterprise came too late and Palace were able to stretch their unbeaten run to five matches.