For the second week in succession a former Palace manager got the better of his former side as Steve Bruce's Hull City side clinched a big win in their battle against the drop at Selhurst Park.
Dame N'Doye was the man who did the damage to the Eagles, scoring twice in the second half to seal a win on a lacklustre afternoon of football in SE25.
Alan Pardew's side will have felt hard done by though as they saw a late Yaya Sanogo header disallowed with the score at 1-0, but it was a rare attempt by the Eagles as they fell to another home defeat.
Palace could easily have found themselves ahead after just six minutes. Jason Puncheon lofted a free-kick into the box which wasn't cleared effectively and it dropped kindly to Glenn Murray at point-blank range but he saw his snapshot blocked by the legs of Steve Harper.
Hull then created a couple of glorious opportunities but squandered them. Firstly Robbie Brady whipped in a corner which was met by an unmarked James Chester but he ballooned a header well over, and then Brady attacked down the left and sent another dangerous cross into the area which was met by N'Doye, but he somehow managed to divert the chance wide when the net should have been rippling.
As Steve Bruce's men cranked up the pressure, Julian Speroni was then forced to make a superb save to push a Tom Huddlestone curler from the edge of the area wide as the visitors continued to cause Palace problems, but the Eagles showed their teeth when Puncheon slipped in Wilfried Zaha who got past Brady and smashed a shot towards goal which forced Harper to make a smart save.
However that was as good as the first-half got for both sides, but on 52 minutes the Tigers got their noses in front in controversial fashion. Sone Aluko switched the ball out wide to Brady who saw the ball strike his arm before he laid it into the path of N'Doye who bundled the ball in from a matter of yards out.
The Senegalese striker should have doubled the lead soon after when he was found in a great position by Huddestone but he slid the ball wide of the far post, but Pardew's side were struggling to get a foothold in the game and could only muster up a snapshot from Puncheon which spun wide of the mark.
The winger then saw an effort from rage flash wide with 13 minutes remaining, and Hull went straight up the other end when Huddlestone let fly but scuffed his shot and it trickled wide of Speroni's goal.
However Palace thought that they had found a leveller with six minutes to go when Pape Souare crossed into the area and substitute Sanogo headed the ball past Harper, but his celebrations were cut short when Mark Clattenberg ruled the goal out for alleging that the striker had pushed over Paul McShane, although replays showed there was minimal contact between the two players.
It was nearly game over with two minutes to go when Liam Rosenior saw a superb volley crash off the crossbar, and then Speroni had to beat away a stinging effort from N'Doye, however in stoppage time they did seal the win.
Chung-yong Lee was caught in possession as Palace pressed for an equaliser and Gaston Ramirez nipped in to steal the ball and slide in N'Doye. The striker composed himself, took a touch and buried the ball past Speroni to clinch a vital win in Hull's battle against relegation.
Palace: Speroni, Kelly, Dann, Delaney, Souare, Jedinak (Lee 65), McArthur, Zaha (Gayle 72), Puncheon, Bolasie, Murray (Sanogo 58). Subs not used: Hennessey, Hangeland, Mutch, Ledley.
Hull: Harper, Brady (Rosenior 84), McShane, Dawson, Chester, Elmohamady, Huddlestone, Livermore, Quinn (Ramirez 74), Aluko (Bruce 85), N'Doye. Subs not used: McGregor, Figueroa, Hernandez, Sagbo.