The margin of victory could, and probably should, have been more convincing, but Watford have done what was required to move within perhaps only a few points of making sure of a third successive season in the Premier League after beating seemingly-doomed Sunderland 1-0.

The decisive contribution came from an unexpected source on the hour, Miguel Britos heading in his first goal for the Hornets from close range having been set up by Craig Cathcart after Stefano Okaka had seen a header turned onto the bar.

Walter Mazzarri’s side had the chances to score more, both before and after taking the lead, but a combination of a disappointing end product and some good saves by the very talented Jordan Pickford ensured the home fans were unable to relax until the final whistle.

And while most of those inside Vicarage Road may not have enjoyed it, the open nature of the contest from the opening whistle made for a surprisingly enjoyable game as both sides took the opportunity to attack whenever possible.

The Watford boss made four changes to the team that lost 1-0 at Crystal Palace two weeks ago and switched formation again, this time going with a 4-3-3.

Mazzarri opted not to start pre-match doubts Troy Deeney and Sebastian Prodl, Valon Behrami was absent with a thigh injury and Daryl Janmaat also dropped to the bench.

Their places were taken by Jose Holebas, Abdoulaye Dooucoure, Okaka and Nordin Amrabat, who made his first start since New Year’s Day.

David Moyes made just the one adjustment from the side that was held to a goalless home draw by Burnley last time out as Lamine Kone returned to the starting XI at the expense of Sebastian Larsson.

The hosts started positively and had the first opening inside 90 seconds when an overhit M’Baye Niang cross from the left ran for Amrabat on the opposite side of the box. He came inside before dinking a left-footed delivery to the back post where Billy Jones just beat Niang to the header.

The resulting corner from the left was taken by Jose Holebas and Niang tried an improvised back-heeled flick which went high and wide of the target.

The Black Cats were also looking to start fast and their first opportunity came when Jermain Defoe laid the ball off to the onrushing Jack Rodwell. He tried to catch Heurelho Gomes out with a lofted left-foot finish which was deflected onto the roof of the Hornets’ net.

Niang and Amrabat switched flanks in the opening stages, with the former having a promising run on the counter-attack but he mis-hit an attempted pass into Okaka.

It was Gomes who was the first keeper to be called into meaningful action in the ninth minute when he had to get down smartly to his right to tip away Adnan Januzaj’s inswinging delivery from the right angle of the 18-yard box.

Watford were looking edgy in the opening stages but they almost took the lead two minutes later when Doucoure came inside on his left foot and hit a low drive which Pickford did well to get down to push over after Etienne Capoue’s slalom break forward had given the home side a variety of attacking possibilities and the Sunderland keeper had first had to push away a Niang cross.

The Hornets’ next attempt was rather more optimistic as a Tom Cleverley corner from the left was headed out to Doucoure, who connected very well with his right foot, but the 30-yard attempt was always swinging wide of the near post.

Soon after Cathcart laid a throw-in into the path of Capoue on the right, he swung over a first-time cross which picked out an unmarked Okaka, but he was unable to direct his header on target.

Mazzarri’s side were continuing to have the better of the attacking exchanges, with Doucoure again optimistically trying his luck from long range before Niang embarked on a threatening run forward which ended with his attempted shot being blocked.

The game was increasingly being played in Sunderland’s half by this stage and Capoue, who was having one of his better halves of football for some time, was the next to go close, fizzing a right-footed strike from the edge of the 18-yard box narrowly wide of the far post with Pickford rooted.

But the Hornets’ injury woes were to reappear again five minutes before the interval when Younes Kaboul came out of a challenge with Defoe, took a couple of steps and then felt the back of his hamstring. He was replaced with Janmaat, with Cathcart moving to central defensive duties alongside Britos.

Moments after play restarted, there were concerned looks back towards the Watford goal when Januzaj hit a shot from the edge of the area which took a wicked deflection, but from the home side’s perspective it deflected the right side of Gomes’ right-hand post.

From the resulting corner though, the Hornets surged forward on the counter with Amrabat leading the charge and as he made his way to midway inside the Black Cats’ half he picked out Niang with a good cross-field pass; the AC Milan loanee struck his shot well enough but the hosts were again thwarted by Pickford, who got down at his near post to block.

The Hornets had another chance from the resultant corner from the left, but Cathcart didn’t connect properly with his attempted header and Pickford saved as an open and, from a neutral’s perspective, enjoyable opening 45 minutes ended goalless.

A stoppage for an injury to Defoe saw the second half start slowly but Watford were soon in the ascendency again, increasing their corner count by a further two.

Another opportunity came and went when Niang showed good footwork on the left side of the area to beat Billy Jones, but although his cross was unable to pick out anyone at the far post that was immediately followed by Isaac Success getting the signal to get ready to come on. He replaced Amrabat in the 53rd minute.

After Jose Holebas had dragged an effort wide, Success saw a volley deflected behind following a corner. But it was from the next set piece that the Hornets were to finally make the deserved breakthrough.

After the ball had been played in from the left, an unmarked Okaka saw his goalbound header turned onto the face of the crossbar by an opponent, Cathcart reacted first to nod back across the face of goal and Britos headed down from close range at the far post to make it 1-0 with his first goal for the club.

Moyes’ response was to bring on Didier N’Dong for Darron Gibson, but the hosts could have made it 2-0 when Okaka’s pass set Success through on goal, Pickford made his latest good save to deny the substitute. But Capoue was first to the loose ball and although he couldn’t get a shot away himself, he teed up Doucoure, whose follow-up was deflected behind.

Having got in front though, Watford got sloppy for a period and they were fortunate not to be punished when Januzaj was set up inside the area, but his shot turned into little more than a pass straight at Gomes.

The hosts were soon back on the front foot, with Holebas striking a fine left-footed drive from 25 yards that could only have cleared Pickford’s bar by about a foot, although referee Lee Probert adjudged it was deflected over.

Moyes made his second change with 20 minutes to go as Wahbi Khazri replaced Januzaj. The substitute’s first real mark on the game was a booking for dissent, coming soon after Jones had also seen yellow for pulling back for Success. And two yellow cards in five minutes for the visitors was to become three in six when Niang’s attempts to make something out of nothing tight to the touchline was illegally stopped by Kone.

Success stung Pickford’s gloves after coming inside to hit a right-footed shot as the hosts continued to seek a second goal to kill the game.

But it needed a good stop from Gomes to prevent Sunderland from equalising with seven minutes remaining when he tipped Fabio Borini’s low drive around the left-hand post following a pass inside from left to right by Khazri.

Watford made their final change with four minutes of normal time remaining as Niang was replaced by Camilo Zuniga. And while their opponents continued to try and get back on terms, the hosts were defending well and deserved to finish the game not only with three points but also a welcome clean sheet.

The home side made life unnecessarily awkward for themselves with a couple of stupidly conceded free-kicks in the closing stages, but Cleverley’s reaction at the final whistle showed what the win meant as he leapt to punch the air in the centre circle.

Watford: Gomes; Cathcart, Kaboul (Janmaat 42), Britos, Holebas; Doucoure, Cleverley, Capoue; Amrabat (Success 53), Okaka, Niang (Zuniga 86). Not used: Pantilimon, Prodl, Mariappa, Deeney.

Sunderland: Pickford; Jones, Kone, O’Shea, Oviedo; Gibson (N’Dong 61), Denayer; Rodwell; Januzaj, Defoe, Borini. Not used: Mannone, Djilobodji, Cattermole, Larsson, Khazri, Manquillo.

Bookings: Jones for a foul on Success (72); Khazri for dissent (77); Kone for a foul on Niang (78); Capoue for a foul on Oviedo (90).

Attendance: 20,805.

Referee: Lee Probert.