Match ends, Stoke City 0, Watford 2.
Troy Deeney and Almen Abdi both scored as Watford spoiled Mark Hughes's 100th game in charge of Stoke.
The Hornets took advantage of a poor defensive display by the Potters, who had won the previous three league games and conceded only one goal.
Deeney grabbed his first Premier League goal with a low strike from Odion Ighalo's pass just before the break.
And Ighalo was provider again when he fed Abdi who smashed his drive past the reach of Jack Butland.
Hughes far from Stoked
Stoke, who came into the match in great form, were inept both in attack and at the back.
Swiss midfielder Xherdan Shaqiri, their record £12m signing, looked League One standard on today's display. The stats showed he provided eight crosses, of which three were good. He was later substituted. And lone frontman Joselu had no efforts on goal in the 61 minutes he played.
But it was the performance at the back that led to Stoke's downfall.
The home side were not helped when Geoff Cameron came off in the ninth minute with an injury, with his replacement, Marc Wilson, having a game to forget.
He joined the group of defenders who have failed to deal with Ighalo this season, and he was made to look silly when he was robbed of the ball by the Nigeria striker prior to the second goal.
Ighalo and Deeney - the best partnership in the Premier League?
The understanding between the pair in attack has been the principle reason why Watford have picked up 13 points and in 13th position.
Captain Deeney, who scored 21 goals in their promotion season, had up until today the most chances of any Premier League player without scoring - 24.
But he finally broke the duck with his 25th. And he had partner Ighalo to thank after the Nigeria striker laid the goal on a plate with a delightful backheel flick.
And what about Ighalo? The 26-year-old, who joined the Hornets on a permanent deal in 2014 after failing to make an impact at Udinese, has been one of the players of the season so far.
Stoke boss Hughes said the Watford strikers "messed" his backline around with Ighalo particularly troublesome.
His second assist for Abdi's goal meant that he has been involved in each of club's last seven Premier League goals, with five strikes and two assists - impressive by any standards.
Man of the match - Odion Ighalo (Watford)
What they said
Stoke manager Mark Hughes asked if that was one of the worst of his 100 games in charge: "It wasn't one of my best. Losing defender Geoff Cameron to injury disrupted us. We had to make changes at the back. We didn't deal with the two up front. We needed to be better than we were today.
"Their two guys up front demand service and they managed to mess us around at the back.
"We will be better than that. At 1-0 down we tried to change things around because we couldn't make any headway. We then made an individual error when Marc Wilson lost the ball leading up to the second goal."
Watford manager Quique Sanchez Flores talking to BBC Sport:
"We tried to play very well. The performance was the main thing. We tried to play with high confidence - it was tough against a Stoke side who came into the match having won the last three.
"After we scored we tried to keep playing a high line. We worked really hard. The balance was amazing between defence and offence.
On striker Troy Deeney getting his first league goal of the season:
"I wasn't worried about the display of Deeney. He has been unlucky so far. Scoring is important for the confidence of strikers. I'm happy for the victory and performance, and happy for the fans."
The stats you need to know
- The Potters have kept just one clean sheet in their last 10 Premier League home games
- Watford won their first Premier League match in October (W1, D4, L6)
- Deeney had yet to score despite attempting 24 shots (including blocked efforts). It was the highest total of any Premier League player yet to score this season
Watford are at home to in-form West Ham, while Stoke face wounded Chelsea in the League Cup on Tuesday before they travel to Newcastle in the top flight next Saturday.
- 20CameronSubstituted forWilsonat 9'minutes
- 3PietersBooked at 89mins
- 16AdamBooked at 90mins
- 6WhelanBooked at 77mins
- 22ShaqiriSubstituted forWaltersat 60'minutes
- 11JoseluSubstituted forCrouchat 61'minutes
- 15van Ginkel
- 21AnyaSubstituted forParedesat 66'minutes
- 22AbdiSubstituted forBehramiat 78'minutes
- 24IghaloBooked at 89minsSubstituted forGuédiouraat 89'minutes
- Martin Atkinson
- Shots on Target
Second Half ends, Stoke City 0, Watford 2.
Offside, Stoke City. Philipp Wollscheid tries a through ball, but Jonathan Walters is caught offside.
Attempt missed. Etienne Capoue (Watford) right footed shot from more than 35 yards misses to the left from a direct free kick.
Foul by Philipp Wollscheid (Stoke City).
Troy Deeney (Watford) wins a free kick in the attacking half.
Offside, Stoke City. Philipp Wollscheid tries a through ball, but Peter Crouch is caught offside.
Charlie Adam (Stoke City) is shown the yellow card for a bad foul.
Foul by Charlie Adam (Stoke City).
Etienne Capoue (Watford) wins a free kick in the attacking half.
Erik Pieters (Stoke City) is shown the yellow card.
Substitution, Watford. Adlène Guédioura replaces Odion Ighalo.
Odion Ighalo (Watford) is shown the yellow card.
Corner, Stoke City. Conceded by Nathan Aké.
Corner, Watford. Conceded by Marc Wilson.
Attempt missed. Marko Arnautovic (Stoke City) header from the centre of the box misses to the left. Assisted by Glen Johnson with a cross.
Offside, Stoke City. Charlie Adam tries a through ball, but Peter Crouch is caught offside.
Marko Arnautovic (Stoke City) wins a free kick in the defensive half.
Foul by Troy Deeney (Watford).
Attempt missed. Etienne Capoue (Watford) left footed shot from outside the box is high and wide to the left.