Derby County inflicted Watford’s first home defeat of the season as Craig Bryson’s late strike earned the Rams all three points at Vicarage Road.
Jordon Ibe gave Steve McClaren’s side the lead towards the end of the first half with a sublime curling effort, before Watford piled on the pressure in the second half.
Substitute Gianni Munari equalised with just over 20 minutes remaining, but after the Rams rode out the Watford storm, Bryson drilled in a late winner to ensure Derby remained top of the Sky Bet Championship.
Built to contain, Watford sat back and allowed Derby to control the early periods of possession.
Their control led to the Rams creating the early chances, first from two successive corners, before Jonathan Bond and the post came to the rescue of the hosts.
Cyrus Christie made headway down the right and after forcing a throw, Derby worked a nice routine of passes, before the ball fell to the feet of Jeff Hendrick on the edge of the area, whose low drive was tipped onto the post by the England Under 21 ‘keeper.
After a prolonged spell of sparring as Watford continued to sit off as Derby and, in particular, Will Hughes dictated play, the hosts carved out their first opening.
Hughes was dispossessed in the centre, Watford, slowly, made their way forward before the ball was played through to Lloyd Dyer who, after wriggling away from Christie, tamely shot straight at Jack Butland.
Both Jordon Ibe and Omar Mascarell had efforts blocked on the edge of the area, before Watford hit the Rams on the break and it took a sublime sliding tackle from Ryan Shotton to deny Odion Ighalo a clean strike on Butland’s goal.
On 25 minutes, Butland was called on to make two fine saves to keep the contest scoreless.
A weak header from Hendrick was capitalised on and after Troy Deeney avoided two challenges, the striker hit a fierce shot that was first palmed then cleared away to safety.
Seconds later, Fernando Forestieri struck from the edge of the area that Butland was, again, equal to as the hosts grew into the game.
Former Hornets man, Craig Forsyth, was next to save Derby as Deeney slipped a pass to Forestieri on the right leaving the Argentine with a clean strike on goal.
Back came Forsyth, though, to get a foot on the ball and clear it to safety, before Bond was called into action at the other end.
As the Rams began to re-establish control, Chris Martin sublimely took down Forsyth’s header before he raced through on goal. The 26-year-old, from the left, shot across Bond’s goal, which was turned away by the ‘keeper from a corner.
With seven minutes remaining, Derby took the lead in superb fashion as Johnny Russell curled a delightful pass out to the influential Ibe, who beat his full back and curled a dipping shot over the outstretched Bond and into the back of the net.
The goal sparked the home side to life and as they launched forward looking for a quick response as Dyer was slipped in behind Christie, but the winger blazed over and wide.
It was the Rams who came close to doubling their lead a minute before the interval as Mascarell curled a precise set piece for Martin to latch on to but Bond turned his firm header over the bar.
Slaviša Jokanović, the Watford Head Coach, introduced Matej Vydra at the interval to add more impetus to his side’s attacking play in the second half, but it was the Rams who continued to lay siege on Bond’s goal.
Russell scampered away down the right hand side and crossed a low ball that evaded everyone in the six-yard box, before the Scottish forward blazed over himself after 54 minutes.
Back came the home side as they began to grow into the contest. First, Deeney saw an effort beaten away by Butland, before Forestieri curled narrowly wide from a central position moments later.
It was Derby, though, that were presented the best opportunity to double their lead after a ball down the left was missed by Juan Carlos Parades and Martin was sent through on goal.
Instead of shooting, Martin tried to step inside Bond and with it narrowed his angle on goal and the ‘keeper read his movement and prevented the forward from getting a shot away.
Forestieri was proving to the hosts biggest threat and as he scampered away down the right, he hit a cross shot narrowly wide of Butland’s far post.
Jokanović introduced Gianni Munari moments later and Watford’s pressure counted as Munari collected the ball on the left and lashed a high effort over Butland.
The hosts came close to turning the game on its head after another sweeping move found Vydra and the Czech Republic international swerved away from one challenge and unleashed a low drive just wide.
With 10 minutes remaining, Forsyth robbed Watford of possession and drove forward before threading a ball out to the right of Russell.
The Scot slipped a ball inside the centre and the left back raced on to the loose ball, but Bond turned his effort away for a corner.
A minute later and the Rams edged back in front in emphatic fashion. A neat and patient move on the left opened up space for Craig Bryson.
The 28-year-old took a touch and opened up his body before striking an effort into the top corner of Bond’s goal.
With time against them, the Hornets began to throw everything at the Derby defence in search of another equaliser.
Ryan Shotton, inexplicably, turned Deeney’s over for a corner, before Anya saw an effort turned over by Butland with four minutes remaining.
Derby rode out the storm and kept their place at the top of the Sky Bet championship after taking yet more points off their promotion rivals.
Watford: Bond (GK); Paredes, Ekstrand, Bassong, Doyley; Andrews (Munari, 62), Tozser; Dyer (Anya, 73), Forestieri, Ighalo (Vydra, 45); Deeney (C)
Substitutes not used: Gilmartin (GK), Angella, Cathcart, Murray, Anya
Derby County: Butland, Christie, Keogh, Shotton, Forsyth, Mascarell, Hendrick, Hughes (Bryson, 66), Ibe (Dawkins, 73), Russell (Coutts, 90), Martin
Substitutes: Roos, Buxton, Eustace, Best
Attendance: 17,421 (2,004 away fans)