Paddy McCarthy scored the only goal of the game as Crystal Palace ended 10-man Ipswich Town's six-game unbeaten run.
The Eagles skipper was in the right place at the right time to toe-poke a low cross from Sean Scannell into the roof of the net.
Jay Emmanuel-Thomas went close for the home side, bringing a superb save out of Julian Speroni.
Scannell could have added a second before Aaron Cresswell was sent off for Ipswich, after two bookable offences.
The win moves Palace up to third in the Championship and they started the game the brighter.
Wilfried Zaha raced away down the right and fired in a dangerous cross, which Damien Delaney deflected just wide of the far post.
Glenn Murray saw a shot cleared by Delaney before the home side had their best chance of the game.
Emmanuel-Thomas fired in a shot from the edge of the box that was tipped over the bar by Speroni.
The breakthrough came on 55 minutes when Ipswich failed to clear a free-kick from Scannell. He whipped in a low cross which McCarthy stabbed home.
Emmanuel-Thomas bought another good save out of Speroni with time running out, when his free-kick was tipped over the bar.