A superb late header from Hull captain Ian Ashbee kept his side in the hunt for automatic promotion and dented Crystal Palace's play-off hopes.
Mark Hudson hit the post for Palace early on, before Hull's Dean Windass smashed a free-kick against the bar.
Fraizer Campbell put Hull ahead on 18 minutes with a sharp finish from 20 yards, but Palace levelled after a defensive mix-up let Scott Sinclair in.
Ashbee converted Dean Marney's corner to settle it on 85 minutes.
•Hull boss Phil Brown is still hopeful of his side earning automatic promotion: "Next weekend is a must-win game, but if the players can handle the pressure against Palace, I'm sure they can against Ipswich.
"We've got here on merit and can finish the second, or maybe even first."
•Crystal Palace boss Neil Warnock:
"The pleasing thing is that it is still in our hands to make the play-offs.
"No-one can complain if we don't make the play-offs, because we've given it a fantastic shot.
"We've already surpassed everyone's expectations this season."
Hull: Myhill, Ricketts, Turner, Brown, Pedersen (Doyle 32), Folan, Marney, Ashbee, Hughes (Barmby 68), Campbell, Windass (Fagan 24).
Subs Not Used: Duke, Walton.
Goals: Campbell 18, Ashbee 85.
Crystal Palace: Speroni, Butterfield, Hill, Hudson, Fonte, Derry (Scannell 87), Soares, Watson, Sinclair (Ifill 70), Morrison, Moses.
Subs Not Used: Ashton, Hills, Bostock.
Booked: Derry.
Goals: Sinclair 38.
Att: 24,350
Ref: R Booth (Sutton Ashfield).
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