It came courtesy of a Tom Lees own-goal early in the match, but both sides had chances to bring more goals to what was a fairly even and hard-fought contest.
The result sees Watford remain comfortably in 2nd place, while Sheffield Wednesday also stay 23rd, six points adrift of safety with eight games remaining.
Story of the game
Coming into the match, Watford manager Xisco Munoz made two changes to the side which secured the comfortable victory over Birmingham City before the international break. Philip Zinckernagel came in for Dan Gosling in midfield, while Ismaila Sarr returned to the side after a knock last time out, taking the place of Ken Sema on the wing.
Sheffield Wednesday boss Darren Moore was absent from the dugout for this game having returned a positive Covid-19 test, but he made just the one adjustment to his team: Sam Hutchinson replaced Liam Palmer in defence.
Nine wins from their last 10 games understandably brewed a tangible degree of confidence in this Watford side, who took the game to their visitors right from the off. With four minutes on the clock, Ismaila Sarr picked the ball up on the right flank and immediately delivered a tantalising cross into the area, which Lees nearly diverted into his own net, forcing Joe Wildsmith into an awkward save.
But the Hornets did manage to take their lead just moments later. Adam Masina played a sumptuous pass out to Sarr on the right flank and the winger controlled the ball before supplying another vicious delivery into that corridor of uncertainty. It looked destined for Isaac Success at the back post, but instead it ricocheted off Lees and into the net.
Wednesday could have equalised with the next chance. Barry Bannan floated a corner to the back post which was then headed back to the edge of the box by Julian Borner. The ball was met by the onrushing Joey Pelupessy, but the Dutch midfielder failed to direct his effort on target.
Watford should have extended their lead just past the 20-minute mark. Joao Pedro picked the ball up on the flank and drove infield, eventually supplying Zinckernagel in the area. The pass was just behind the Dane, so he spun and fed Success to his right, but the striker took to long to register his shot and Wednesday were able to clear.
In truth, following Watford's bright start this was a fairly even first half, with both sides as comfortable without possession as they were with it. Bannan was orchestrating most of what worked for the visitors, on one occasion threading the ball through to Josh Windass behind the Watford defence but, like Success, he failed to control the ball in time to get his shot away.
The best chances the visitors would have of taking something from this match would likely arise from set-pieces. Another Bannan delivery was cleared awkwardly by William Troost-Ekong, the ball eventually dropping for Borner just inside the box but his effort sailed wide of the mark.
The hosts were pushing hard to score that crucial second goal before half-time. Zinckernagel's quick feet won him a free-kick just 20 yards out and to the left of goal, and the midfielder stepped up to take it, only to see his arrowed shot towards the top corner saved by Wildsmith.
Their last opportunity came in first-half stoppage time. Troost-Ekong booted the ball up to Success who flicked it on for Pedro behind the Wednesday defence. The Brazilian drove forward and aimed at goal on his left foot, but it agonisingly sailed just wide of the far post wide, and the early own-goal would be all that separated the sides heading into the break.
Wednesday worked the first chance of the second half. Some headed pinball in midfield eventually saw it drop for Callum Paterson, who juggled forward several steps before unleashing a vicious dipping effort on the volley. It whistled just over the bar, but Bachmann looked to have it covered.
The tempo visibly ramped up a notch or two after the break, with Watford particularly desperate to consolidate their lead by scoring the next goal. First, Pedro weaved into the area and left Osaze Urhoghide for dead with a clever feint before firing straight at Wildsmith from a tight angle. Possession was then recycled and laid off for Sarr on the edge of the box; the Senegal international aimed for the far top corner, but it as high and wide of the mark.
Unfazed by the form of their opponents, the visitors were still very much in this game. A pass was lofted into the area by Bannan and pressure from Windass made it difficult for Francisco Sierralta to clear properly. It then dropped for Jordan Rhodes at the back post, and it looked for all the world that the striker couldn't miss from six yards out — but that he did, skewing his shot and spurning his side's best opportunity of the match thus far in what was a real let-off for Watford.
Watford were struggling to break Wednesday down, but they can often turn to one man in particular to make things click. Sarr did just that when he tussled with both Borner and Bannan, eventually wrestling free of challenges from both of them and crossing from the byline, but Urhoghide nipped in with a crucial intervention before Ken Sema could prod home.
The final chance of a scrappy second half fell to Sarr, the inspirational spark of a slightly off-the-pace Watford side today. It dropped for him on the edge of the box following a corner and the Senegalese took it on first time, but it soared high and wide of the target.
Watford got over the line to secure their 10th win in 11 games; this performance may not have been their most assured in that run, but their promotion credentials are strengthening by the week, and they are now in a great position to secure that second automatic promotion spot. For Wednesday, meanwhile, life in the third tier looms unless they can pick their form up, and pronto.
Takeaways from the match
All Watford need to do is get the job done
This was not the prettiest of Watford's recent victories; they struggled to create openings in attack, but also worked sheepishly through a few shaky moments defensively. Perhaps the international break provided an unwelcome pause to the momentum they'd gathered prior, but the Hornets weren't really up to speed today.
But all that will matter to Munoz and his men is the result. These are three crucial, hard-earned points, and as long as they keep securing those, they'll be on their way straight back to the Premier League.
Time is of the essence for Wednesday
The Sheffield outfit matched their promotion-chasing hosts in most aspects of play today, but return home with nothing to show for it.
Wednesday are clearly a side with quality in their ranks — Bannan in particular was superb today — and it is thus not unthinkable for them to defy their six-point deduction and survive, but time is running out, and fast. They have eight more games to dictate whether they will participate in the Championship or League One next season, and the message is clear: they need to start winning.
Watford: Bachmann; Femenia, Troost-Ekong, Sierralta, Masina; Chalobah (Sanchez 84'), Hughes, Zinckernagel (Gosling 60'); Sarr, Success (Gray 61'), Pedro (Sema 71').
Unused subs: Foster, Ngakia, Kabasele, Lazaar, Hungbo.
Sheffield Wednesday: Wildsmith; Urhoghide, Lees (Shaw 85'), Borner; Paterson (Green 82'), Hutchinson, Bannan, Pelupessy (Palmer 77'), Reach; Rhodes, Windass.
Unused subs: Jackson, Penney, Hunt, Brown, Harris, Kachunga.
Following victory here, Watford travel to the north east to face playoff chasers Middlesbrough on Easter Monday.
Meanwhile, Sheffield Wednesday return to their home of Hillsborough, with Cardiff City their visitors.