Odion Ighalo's 10th Premier League goal of the season proved decisive as Watford made the most of a breathtaking start at the Stadium of Light to beat Sunderland 1-0 on Saturday.
The Nigeria striker proved a nuisance throughout, with his ability on the ball troubling the Sunderland defence, but it was his clever movement in the fourth minute which made the difference as he turned in Allan Nyom's low cross.
Ighalo, who became the first player to reach double figures in a single Premier League season for the club, almost had another shortly after but saw his attempt cleared off the line just a few seconds before the post denied Jose Manuel Jurado.
Sunderland managed to gain some composure as the first period progressed and then started the second half on top, putting the Hornets under significant pressure.
That superiority ultimately came to little, though, as Watford defended excellently and sought opportunities on the counterattack, holding out for all three points to edge towards the top five.
Sunderland's DeAndre Yedlin insisted in the build-up that promoted Watford were "very beatable", but the visitors' start did little to back up the American's claim, as Ighalo opened the scoring.
Jurado fed the surging Nyom on the right and the defender's low cross was expertly turned in by the in-form Nigerian under pressure from Sebastian Coates.
Sunderland somehow avoided going two down six minutes later, with Ighalo their chief tormentor again, brilliantly turning John O'Shea in the area before seeing an effort blocked on the line by Coates. Jurado then struck the post in the ensuing penalty area scramble.
Clearly unimpressed with his team's start, Sunderland boss Sam Allardyce hauled off Yedlin after just 19 minutes, though that did not stop Watford carving through Sunderland again just before the half-hour mark, with Etienne Capoue testing Costel Pantilimon from 20 yards.
The home side eventually settled and created their first chance of note with 43 minutes gone, as Heurelho Gomes was forced into action to prevent a headed own-goal from Watford centre-back Miguel Britos following Yann M'Vila's fine left-wing delivery.
Sunderland's improvement was not halted by the half-time break and only the sprawling Gomes kept Watford's lead intact in the 53rd minute, thwarting Jack Rodwell's 30-yard drive.
Watford remained stubborn defensively and let little else through, with Gomes staying largely untroubled despite the hosts' superior possession.
Sunderland looked at their most threatening from distance and the lively Duncan Watmore did go close in the 79th minute, but his powerful effort flew just wide.
Gomes then excelled himself with a fine save to push Jermain Defoe's shot wide of the post before the former Tottenham striker glanced Patrick van Aanholt's volleyed centre inches off target shortly afterwards.
As Sunderland pushed forward, Watford found space at the other end and only a low block from Pantilimon prevented Ighalo from adding another in the closing seconds.
