After 23 minutes, Victor Moses was booked for a foul on Preston right-back Billy Jones, who was running through on goal down the right-hand side 30-yards out.
Ben Watson had a 20-yard right-foot shot which was on target and was saved by Preston keeper Andy Lonergan.
Paul Ifill was booked for deliberate handball in the penalty area when he was trying to score following a left-wing cross after 31 minutes.
Chris Brown took a short free-kick to Darren Carter as the Palace players were protesting to the referee and he hit a 25-yard left-foot shot which went over the bar.
Ifill had a 12-yard left-foot shot from the middle of the penalty area which Lonergan parried and Jones was booked for a foul on Moses in the centre of the pitch.
One minute was added to a goalless first half.
At half-time Preston made a double substitution, bringing on Lewis Neal and Neil Mellor for Simon Whaley and Karl Hawley respectively.
Moses had a right-foot shot from the right which was saved and Palace brought on Dougie Freedman for Ifill.
Preston's best effort came in the 68th minute when Chris Sedgwick had a 20-yard right-foot shot from the right channel which was kicked over the bar for a right-wing corner by Palace keeper Julian Speroni.
Mellor had an 18-yard right-foot shot from the left saved for a right-wing corner.
Palace scored the all important goal after 75 minutes when a header on target and assisted by Moses from eight yards out was turned in by Clinton Morrison's chest from six-yards.
An injured Carter was booked for dissent and Brett Ormerod came on for Sedgwick.
Matt Hill was booked for a foul on Moses and Ashley Robinson replaced him.
Right at the end Watson was booked for time wasting.