James Vaughan's strike in the last ten minutes of the first half saw Palace move out of the relegation zone after&nbsp;a 1-1 draw at Vicarage Road.
Dougie Freedman made two changes to his starting line-up as Wilfried Zaha returned in place of Sean Scannell and Adam Barrett came in for Anthony Gardner.
With Watford having won their last four league games at home and Palace having won just once on the road this season a home win seemed the most likely result, and it was the Hornets who threatened first with Andros Townsend pulling the strings as he almost got Andy Weimann away.
Weimann didn't have to wait long to open the scoring though.&nbsp;Townsend again&nbsp;broke away down the left and cut inside Nathaniel Clyne, his ball inside finding the Villa loanee and he made no mistake firing past Speroni into the bottom corner.
With Stephen McGinn impressing centrally, Watford's front-two and in particular Weimann were threatening to put the game out of sight before half-time.
Palace fought back well though with first Darren Ambrose testing Scott Loach with a free-kick and then&nbsp;the midfielder&nbsp;winning a free-kick right on the edge of the area which Watford did well to clear at the far post.
Again Watford threatened though and Danny Graham was inches away from making it two then&nbsp;when he almost latched on to Weimann's cross at the far post.
With just&nbsp;five minutes to go to the break, Zaha broke through the centre and found Vaughan's clever movement with a slide-rule pass. Vaughan took one touch before smashing the ball past the despairing Loach.
Just before half-time Adrian Mariappa had a&nbsp;free header from a Watford corner but headed over with the goal at the mercy and the sides went into the break locked at 1-1.
As the second half began, the pitch was enveloped in fog but Palace weathered the early storm&nbsp;as Danny Graham looked threatening for the home side.
Townsend hit the hall with a free-kick before Clyne was booked for a foul on the tricky winger but Palace continued to look solid at the back. Looking to inject some pace&nbsp;on the flanks, Freedman introduced Scannell with twenty minutes of the second half gone. Great trickery from Zaha on the right almost had Palace in front minutes later but Watford held firm at the back.
Danny Drinkwater then came on for Andros Townsend as Mackay looked to win the game and Graham soon went close on the break for Watford before setting up Eustace for a low drive that, the barely visible, Speroni did well to save. Another Graham effort curled just wide as the Hornets pressed for a winner, and Davis replaced Zaha as Freedman looked to shut up shop.
Two corners in the dying minutes saw Watford go close before the officials announced six minutes of injury time and a Graham free-kick had hearts in mouths but Palace stood firm for a point that took them out of the relegation zone.
Watford Loach, Hodson, Taylor, Mariappa, Doyley, Eustace, McGinn, Buckley (Whichelow 74), Townsend (Drinkwater 65),Graham, Weimann (Deeney 88).
Subs Not Used: Gilmartin, Bennett, Kiernan, Mingoia.
Crystal Palace Speroni, Clyne, McCarthy, Barrett, Parsons, Wright, Ambrose (Scannell 62), Danns, Zaha (Davis 88), Marrow,Vaughan (Easter 77).
Subs Not Used: Price, Iversen, Garvan, Counago.
Booked: Barrett, Clyne, Zaha, Wright.
Att:12,664 (1,652) Ref: Mr K Stroud