Nigel Pearson was a relieved man as Neil Danns came back to haunt his old club and handed the Leicester boss his first away win since returning to the Foxes.
Danns scored one from a lucky rebound and made the second with a free-kick nodded in by Sol Bamba against a Palace side badly hit by a virus sweeping the club.
Jonathan Parr pulled one back for the hosts just before half-time with a cross that ended up in the net, before Steve Howard saw red late on for the Foxes for foul and abusive language.
But the dismissal took nothing away from Pearson's relief as it ended a five-game winless run.
He said: "For us it is an important win. We have been without a win for a few games. It has been a frustrating time for us.
"
The expectations on our season are such that we have found ourselves in a position where we are playing catch-up.
The best thing about the game is the result and the fact the players showed a lot of character.
It wasn't pretty, but we got the win."