Jermaine Easter's first-half strike against his former club Millwall secured a south London derby victory for Crystal Palace to keep them in touch with the play-off places.
Wilfried Zaha started a slick move before Darren Ambrose supplied Easter, who prodded in from close range.
Millwall wasted an excellent chance to equalise when Dany N'Guessan missed a header from two yards out.
Palace's Jonathan Parr cleared a Paul Robinson header off the line late on.
The win provided revenge for the Eagles, who had sacked their manager George Burley after a 3-0 defeat by the Lions on New Year's Day last season, a result which left them deep in relegation trouble.
They took the lead after 23 minutes of scrappy football, Zaha and Chris Martin combining to play in Ambrose, whose first-time cross was met by Easter.
The visitors could have made it two on the half-hour when Ambrose's corner fell to Mile Jedinak at the far post but his shot was tipped over by Steve Mildenhall.
N'Guessan then saw his close-range header from Hamer Bouazza's cross bounce high and wide, but Mildenhall in the Millwall goal was the busier keeper as half-time approached, keeping out Ambrose's free-kick and denying Zaha.
After the break, Trotter headed just over from Bouazza's corner and the midfielder also saw a shot from the edge of the area clear the crossbar.
The Lions thought they had equalised with 15 minutes to go through their skipper Robinson but Parr's clearance ensured Palace took the points.