The Eagles avoided an upset at the Eco-Power Stadium on Monday night to set up a tantalising home tie against fellow south Londoners Millwall.
Colombia wing-back Munoz made the breakthrough on 31 minutes from a well-worked free kick before Northern Ireland international Devenny put the game beyond reach early in the second half.
"As long as you are in the competition you can win it," Palace manager Oliver Glasner said.
"We will go for it. I don't know if it will work but we will go for it, definitely.
"I'm pleased with the performance ... Credit to Doncaster, they had a good match plan and it was difficult to find space."
Palace went ahead with their first chance of note. Daichi Kamada's clever low free kick found Jean-Philippe Mateta, whose shot cannoned back off the post but left Munoz with a simple tap-in.
Rovers continued to hold their own and Luke Molyneux and Rob Street combined to find 39-year-old striker Billy Sharp, whose shot on the turn was held by Matt Turner.
A minute before halftime Owen Bailey dispossessed Will Hughes and found Molyneux, who cut in from the right before drilling a low effort from the edge of the box narrowly past the post.
Glasner brought Ben Chilwell on at halftime for his Palace debut as the England full-back played his first minutes since appearing as a substitute for Chelsea in September.
Just as the promotion chasers looked to be building some momentum, Palace launched a 55th-minute break and Hughes played a clever ball over the top to allow Devenny to convert a second.
Molyneux twice went close again for Doncaster after 60 and 75 minutes, respectively.
Rovers skipper Bailey was denied by a good low save after the ball broke loose in the Palace box in the 81st minute but, for all their endeavour, the home side were unable to find a consolation.
On facing south London rivals Millwall in the next round, Glasner added: "I could feel the excitement in the dressing room.
"It makes this game even bigger than it is - against any other team the target and the goal is the same, to win the game and get into the quarter-final."
FA CUP FIFTH-ROUND DRAW:
Preston North End v Burnley
Aston Villa v Cardiff City
Crystal Palace v Millwall
Manchester United v Fulham
Newcastle United v Brighton & Hove Albion
Bournemouth v Wolverhampton Wanderers
Manchester City v Plymouth Argyle
Exeter City or Nottingham Forest v Ipswich Town
Ties to be played across the first weekend of March.
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