Swansea City came to the Vic in search of points under new boss Carlos Carvahal, and despite going ahead and controlling much of the game, the Golden Boys were sunk by two late goals.
André Carrillo opened the scoring, and gave Watford something to show for their first-half efforts at the break, but a late comeback from the Swans saw Jordan Ayew and Luciano Narsingh steal three points from the hosts.
Ayew gave the Hornets an early scare when he hit the bar five minutes in. Gomes was backpedalling and will have been relieved to see the Ghanaian’s speculative effort hit the woodwork.
Tom Cleverley then had Łukasz Fabianski scampering across goal just moments later, as he shaped to shoot on the left-hand side of the box, but saw his effort curl just wide of the far post.
It didn’t take the hosts much longer to find the net though, with Carrillo netting his first in a Watford shirt in the 11th minute.
Stefano Okaka, in his first start since the opening day of the season, did well to win the ball in midfield. The striker drove out towards the left, before threading a fine pass through to Richarlison. The Brazilian’s shot was saved by Fabianski, but Carrillo was there to head in on the rebound - a deserved reward for his performances in recent weeks.
The game quietened down a bit after the goal, with the only real chance coming just before half-time.
Richarlison tested Fabianski at his near post with a header, after Daryl Janmaat had swung a cross into the box from a deeper position, but his attempt on goal was easily held by Swansea’s man between the sticks.
Watford continued to push for a second after the break, with Richarlison, Carrillo, Okaka and Cleverley combining well going forward.
Carrillo fed Cleverley, who neatly shifted his feet to put Richarlison through, and the winger slid the ball across the face of goal with Okaka sliding in unable to get a touch.
The Golden Boys' attacking players seemed to be enjoying themelves, as Okaka strode his way through the Swansea box – getting to the byline while holding off two defenders – but unfortunately his cutback was just behind Richarlison and was cleared for a corner.
Molla Wagué then thought he had the ball in the net from the set-piece, but it was ruled out for a foul as he competed for the ball.
Andre Gray could have added another in the closing stages after being brought on, as fellow substitute Roberto Pereyra played a perfect ball with the outside of his foot through the Swansea backline to give him an opportunity to seal three points for the Golden Boys, but his shot was well-saved by Fabianski.
And Swansea struck with just four minutes remaining to punish the Hornets for their profligacy. Swans’ substitute Oliver McBurnie knocked the ball down to Ayew, who poked in from close range. The goal given despite Watford’s protestations of offside.
To add insult to injury, the visiting side slotted another past Gomes in injury time, after the Brazilian had parried Nathan Dyer’s long-range shot back out into the area.
Luciano Narsingh was the quickest to react in the box, tapping home to complete the turnaround. Again, there was a possible offside, but nothing was given and Swansea saw out the game keeping the ball in the corner by the ecstatic away fans.
Watford will now have to pick themselves up and go again, facing possibly their toughest test so far this season – Manchester City away.
HORNETS: Gomes (GK)(c); Janmaat, Wagué (Prödl ’64), Kabasele, Zeegelaar; Doucouré, Watson; Carrillo (Pereyra ’83), Cleverley, Richarlison; Okaka (Gray ‘77).
Subs not used: Karnezis (GK), Holebas, Capoue, Sinclair.
Bookings: Carrillo (’30), Doucouré (‘80), Prödl (’82), Zeegelaar (‘89).
Goals: Carrillo (’11).
SWANS: Fabianski (GK); Naughton, Fernandez (c), Mawson, Olsson; Clucas (Dyer ‘79), Mesa (Narsingh ’45), Carroll; Sanches; Ayew, Abraham (McBurnie ’56)
Subs not used: Nordfeldt (GK), Van der Hoorn, Fer, Rangel.
Bookings: Fernandez (‘3), Carroll (’34).
Goals: Ayew (‘86), Narsingh (’90).