Former Sunderland defender Patrick Van Aanholt scored the winner to lift new side Crystal Palace out of the bottom three and level on points with Middlesbrough.
Van Aanholt, brought to Selhurst Park by Sam Allardyce in January, coolly curled an effot from the edge of the area past Boro keeper Victor Valdes after 34 minutes.
It proved enough to beat Boro, who have not won since before Christmas and remain the lowest scorers in the Premier League.
More to follow.