The Eagles avoided an upset at the Eco-Power Stadium on Monday night to set up a home tie against fellow south Londoners Millwall, despite struggling to create chances against a well-organised Rovers outfit who failed to make the most of their own opportunities.
Colombia wing-back Munoz eventually made the breakthrough from a well-worked free kick before Northern Ireland international Devenny put the game beyond reach early in the second half.
The League Two hosts were first to get an effort on goal as good work down the left by James Maxwell and Luke Molyneux led to 39-year-old striker Billy Sharp laying the ball off for Ethan Ennis, whose tame shot from the edge of the area was comfortably saved by Matt Turner.
Palace went ahead with their first chance of note in the 31st minute. 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 Molyneux and Rob Street combined to find Sharp, whose shot on the turn was held by 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.
Oliver 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 a League Cup tie against Barrow 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.
Doncaster could have pulled one back on the hour mark but Molyneux shot straight at Turner after being cleverly played in by Sharp.
Molyneux went close again after 75 minutes, cutting in onto his left foot before narrowly firing over the bar from 20 yards.
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.
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