Owen Garvan starred for Crystal Palace with two goals in four second half minutes to hand the Eagles victory and end the club's three game run without a defeat.
His goals arrived in an amazing ten minute spell in which both sides scored two apiece, but fortunately for the Eagles Darren Ambrose's 18th minute stunning opener proved decisive.
The midfielder, in his first full home league start since August, curled in a 25-yard effort to give the home side the lead going into the break, but Watford responded with two quick fire efforts from Danny Graham and Jordon Mutch before Garvan won it for Palace with his super double.
Watford came into the game looking for their first win since mid-October, and started off by drawing&nbsp;first blood through John Eustace. The veteran midfielder&nbsp;struck a difficult 30 yard effort that swerved and dipped infront of Speroni, and Palace's keeper looked content in getting anything to it as he bundled it clear of his goal.
At the other end, Scott Loach almost gifted the Eagles the early advantage when he got himself involved in some defensive confusion with Martin Taylor. Their dawdling allowed Pablo Counago to nip in and steal the ball,&nbsp;but the Spaniard's first touch took him wide and the ball ran into the path of Ambrose, whose shot was deflected wide.
Moments later,&nbsp;James Vaughan showed his striker's instincts with a turn and shot&nbsp;that was always going to be difficult to control having taken it with his back to goal and off balance. &nbsp;
In the end though, Palace's good start was rewarded with a brilliantly worked counter attack that&nbsp;started with a Danny Graham effort in the Palace box.
With Speroni stranded Paddy McCarthy did brilliantly to block the effort, and the ball fell to&nbsp;Garvan just outside the box.
The midfielder carried it midway into Watford's half before trying to release&nbsp;Vaughan through, only for Adrian Mariappa to block it with an outstretched leg. Ambrose then picked it up, had a quick look before curling a right footed effort over a despairing Loach for his second of the season.
While most in the ground expected the goal to lift the Eagles even further, it appeared to have a completely opposite effect and instead they looked nervy and began to lose out to Watford in almost every department.
On 24 minutes Graham should have levelled the scores when he was free inside the box, but the striker snatched at his strike and fired it across goal.
It was a chance all of Palace's&nbsp;making as they failed to clear properly from a Stephen McGinn effort that was saved by Speroni. That&nbsp;allowed Watford to play it&nbsp;back into the danger area and to the feet of Graham.
Lloyd Doyley then wasted a free shot from 18 yards by smashing it over the bar, while Graham then put a header wide as the Eagles again failed to clear their lines from a corner.
Speroni was then called into action with a brilliant reaction save as McGinn looked certain to score with a volley at the back post, while Danns finished a short spell of pressure right at the end of the half with an awkward 25-yard effort that Loach parried away to safety.
The second period began just as the first had finished; Palace looked edgy and Watford&nbsp;dominated.
And it didn't take them long&nbsp;to turn that dominance into an equaliser - three minutes into it in fact, as Graham eventually found the target with a simple tap in.
Alex Marrow lost the ball in midfield to Mutch, and the youngster drove forward before releasing McGinn down the left and his cross across the six yard box was easy for Graham.
Four minutes later the turnaround was complete as another flowing Watford move ripped through the Eagles defensive lines. McGinn received the ball on the edge of the box and quickly played in Mutch with a neat flick, and the young midfielder did the rest with a neat finish across Speroni and into the bottom corner.
George Burley responded by bringing on Wilfried Zaha for Counago and the youngster had an immediate impact.
Picking the ball up down the right channel, and shadowed by two markers, he showed some of the masterful skill we are growing accustomed to with a clever back heel that&nbsp;took him free.
Looking up he tried to pick out Neil Danns but the ball was deflected out to the edge of the box where Garvan was waiting to smash it into the bottom corner to level for Palace.
While that one was a perfect example of clinical, precise finishing his second of the evening was one for the end of season show reels.
A free kick deep into the Watford box was not cleared properly at the first attempt, and at the second Garvan stormed onto it and met it with a ferocious half volley that left Loach with no chance.
Again though, once the Eagles had the lead they suddenly began to look nervous with it, and invited Watford to get on the front foot; an invitation that Mutch looked to accept when he forced Speroni into a neat save down to his left from 25 yards out.
However, it was the Argentine's counterpart who stole the accolades for the finest save of the night when Loach somehow managed to get an outstretched hand to McCarthy's point blank header to save it on the line.
But he looked a lot more shakey when Zaha left Lloyd Doyley for dead and fired in a fiery effort that he couldn't keep hold of, and fortunately for him it took Ambrose by surprise on the follow up.
Nathaniel Clyne then showed why he is more comfortable at right back than up front when he smashed an effort wide with only the goalkeeper to beat. The youngster's overlapping run was picked out by Ambrose, and with noone closing down he took his time to pick his spot but rushed the strike and fired it into the side netting.
With nine minutes remaining, a training ground set piece routine almost provided the breakthrough for Watford in their search for an equaliser when, with everyone expecting them to whip the ball into the box, it was instead played across the 18 yard line to McGinn whose effort flew inches wide of Speroni's left hand post.
The Hornets huffed and puffed in the dying minutes, but some solid defending from the Eagles saw the game out and the referee blew up to send the Palace support into raptures.
Attendance: 12,353 (Away: 832)
George Burley has made no changes to the starting XI that travelled up to the Riverside, but Claude Davis has returned from his suspension and is a substitute.
Crystal Palace: 1. Julian Speroni; 2. Nathaniel Clyne; 3. David Wright; 5. Paddy McCarthy; 6. Adam Barrett (4. Claude Davis; 73); 7. Darren Ambrose&nbsp;(25. Alassane N'Diaye, 83); 8. Neil Danns; 9. James Vaughan; 10. Owen Garvan; 30. Alex Marrow; 32. Pablo Counago (16. Wilfried Zaha, 55)
Subs: 35. Charlie Mann;15. Kieron Cadogan;&nbsp;&nbsp;21. Kieran Djilali; 29. Jonathan Obika
Watford: 1. Scott Loach; 3. Andy Taylor; 4. John Eustace; 5. Martin Taylor; 6. Adrian Mariappa; 9. Troy Deeney; 10. Danny Graham (20. Marvin Sordell, 78); 12. Lloyd Doyley; 15. Stephen McGinn; 18. Jordon Mutch; 24. Matt Whichelow (11. Will Buckley, 62)
Subs: 2. Lee Hodson; 8. Josh Walker; 13. Rene Gilmartin; 16. Michael Bryan; 17. Dale Bennett