Arsenal missed the chance to go eight points clear at the top of the Premier League in a turgid 0-0 draw with champions Liverpool.
First-half goals by Jakub Kiwior and Leandro Trossard looked like being enough for a lacklustre Arsenal against a lively Palace side who equalised with an Eberechi Eze volley.
Arsenal became the highest-profile casualties of the FA Cup third round as the 14-time winners lost 1-0 at Nottingham Forest, but Liverpool and Tottenham Hotspur avoided early exits after scares against lower-league sides on Sunday.