Slaven Bilic’s first home game in charge of Watford has ended in defeat after Swansea City came from behind to win 2-1 at Vicarage Road tonight.

The Hornets were undone during what proved to be a staggering 20 minutes of time added-on at the end of the second half – the game suffering a lengthy delay due to a problem with the officials’ communications equipment – due to their own defensive shortcomings when Ben Cabango was given the freedom of the penalty area to head in a free-kick.

The hosts started poorly and struggled to get any real semblance of control during the first quarter of the contest, but once they finally began to add an intensity to their game Swansea’s early control and confidence began to diminish.

Keinan Davis saw the Hornets’ first clear opening blocked but soon after Ismaila Sarr gave the hosts the lead on his 100th appearance for the club.

Swansea were to be level early in the second half though, when Olivier Ntcham fired home a deflected shot from the edge of the area - and it was the visitors who finished the stronger when the match finally restarted after the prolonged delay, sealing the points when Cabango was left completely unmarked to head home.

With no fresh injury problems and none of those players currently sidelined ready to return, Bilic stuck with the same starting XI that got his time at the Vicarage Road helm off to a winning start with a 4-0 victory over Stoke City on Sunday.

That meant Imran Louza, who impressed during his 30-minute return to action, again started on the bench, but there was no Kortney Hause among the substitutes, with Mattie Pollock replacing him.

Swansea came into the game off the back of three wins in their last four and boss Russell Martin made two changes from the team which won 3-2 at West Bromwich Albion at the weekend, with Michael Obafemi and Ntcham replacing Luke Cundle and Ollie Cooper.

Watford put themselves under pressure almost immediately as Mario Gaspar and then Christian Kabasele conceded possession from attempted passes, leading to Hamza Choudhury conceding a free-kick on the left angle of the penalty area. However, Ntcham sent his initial strike into the wall and then sliced the follow up high and wide.

The visitors continued to dominate the opening exchanges, zipping the ball around confidently, while Kabasele’s inauspicious start to the contest continued, scuffing another attempted clearance before mistiming an attempted header from a cross.

That set the tone for an awful first 15 minutes from the Hornets as they struggled to get semblance of controlled possession, but often found themselves totally outnumbered in the central areas.

There was finally a suggestion of better things to come in the 18th minute when Yaser Asprilla managed to spin away and work some space on the right side of midfield, leading to a spell of possession in and around the Swans’ 18-yard box but it failed to yield a clear attempt on goal.

The Hornets were often playing the ball back and square, which began to audibly test the patience of some sections of the home support by midway through the half, but that frustration did lead to the hosts upping the intensity and enjoying more of the ball in the opposition half. And it began to result in opportunities.

Choudhury intercepted a pass in the 30th minute, leading to Sarr finding Davis on the left side of the area and the striker shifted the ball on to his left foot before seeing his shot blocked by keeper Steven Benda.

The next opening saw the Swansea keeper picking the ball out of his net.

Hassane Kamara lifted the ball down the left to Davis, who’d pulled out wide. He slipped it infield to Ken Sema, who showed some great feet to trick his way past Kyle Naughton before drilling a low cross into the six-yard box where Sarr got across his man to cap his 100th Hornets appearance with a goal.

That seemed to settle the Hornets down but it looked like they had been pegged back three minutes before the interval when Gaspar conceded a free-kick on the edge of the area. A well-worked set piece saw the ball knocked square to Matt Grimes, whose low left-footed strike was spilt by Daniel Bachmann and Obafemi gratefully capitalised on the rebound, only for his celebrations to be cut short by the linesman’s offside flag.

However, the hosts then went close to doubling their lead when Asprilla picked Naughton’s pocket and advanced, taking the ball confidently around Benda, only to see his attempted right-footed finish blocked on the line by Nathan Wood.

Watford safely navigated five minutes of injury time, although Asprilla did pick up an injury in the latter stages, and Louza was soon out on the pitch warming up. However, there were no changes at the start of the second half.

It was the visitors who were to first to ask an attacking question after the break, with Obafemi seeing a shot from the edge of the area deflected wide of the near post.

Kabasele made a better start to the second half than he did the first, first dispossessing Ntcham and then producing a fine sliding challenge on Ryan Manning when the visitors threatened to break. But the Swansea forward was not to be kept at bay for much longer.

Grimes started the sharp end of a move with a pass to Ntcham who advanced before switching the ball on to his right foot, doing enough to wrong-foot Kabasele before hitting a right-footed shot from the edge of the area which deflected off the centre-half and beat Kabasele at his near post to make it 1-1.

Swansea had their feathers up and Bilic moved to try and regain some control by bringing on Louza for Asprilla after 55 minutes.

The substitute’s first real involvement was to get involved needlessly after conceding a free-kick, but at the same time Gaspar went to ground, gesturing to the bench that he was unable to continue. James Morris came on in his place on the hour for his league debut, going to left-back, with Kamara moving over to the right side of the defence.

The replacement started confidently enough, sweeping a cross-field pass out to Sarr with his first touch before striking a cross moments later. Indeed, he was quickly to become a willing outlet on the left, getting forward to help the Hornets’ attacks as much as possible.

Manning hit a speculative effort across goal at the other end before Grimes was the first player to be booked in the 67th minute for pulling back Louza at a time when the hosts were having the better of the exchanges.

Indeed, Benda had to make himself big to prevent Kamara from putting the Hornets back in front when a Sarr cross was headed back across the face of goal to the full-back on the angle of the six-yard box.

The Swans made their first change after 71 minutes when Cooper came on for Ntcham, but it was their opponents who having most of the attacking play as a stretching Davis sent a header wide from a cross.

Swansea introduced Joel Latibeaudiere for Matthew Sorinola after 77 minutes, but at the same time the home side were forced into another injury-enforced change as Francisco Sierralta made way for Pollock, while Vakoun Bayo was introduced for Davis.

Soon after though, Louza played a stunning cross-field pass that looked to put Sarr in behind the defence as he broke into the area from the right, but Manning timed his challenge spot on to concede a corner.

What followed was all a bit farcical as the game was paused for several minutes due to a problem with the officials’ communications equipment, but both sets of players remained on the pitch as chants of ‘you’ve got a flag and a whistle’ reverberated around the stadium.

The game finally restated with a Watford corner but it was Swansea who had the first chance after the lengthy stoppage, and it was a good one, Joel Piroe found in space in the area but it was unable to beat Bachmann was attempted left-footed finish.

The signalling of an additional 17 minutes of stoppage time underlined how long the delay in proceedings had been, but it was the visitors who were having more of the ball as the game entered its belated latter stages.

And they paid a heavy price seven minutes into the time added on when Manning floated in a free-kick from the left and Cabango was given the freedom of the penalty area to head the visitors in front with ease. It was a defensively diabolical goal to concede.

Tempers began to get frayed after that, with Swansea doing all they could to run down the clock before there was even more drama as the second half ticked into its 20th minute of added time.

Louza played in a deep cross from the left and Bayo and a teammate flung themselves at the ball at the far post, both failing to make contact. The Hornets appealed strongly for a penalty and referee Tim Robinson went over to consult his linesman before awarding a goal kick, signalling the end of Watford’s hopes of salvaging something from the game.

Watford: Bachmann; Gaspar (Morris 60), Kabasele, Sierralta (Pollock 77), Kamara; Choudhury, Kayembe; Sarr, Asprilla (Louza 55), Sema; Davis (Bayo 77). Subs not used: Okoye, Gosling, Hungbo.

Swansea City: Benda; Wood, Naughton (Darling 90+10), Cabango; Sorinola (Latibeaudiere 77), Ntcham, Fulton, Grimes, Manning; Piroe, Ntcham (Cooper 71); Obafemi. Subs not used: Fisher, Cundle, Oko-Flex, Stevens.

Bookings: Grimes for a foul on Louza (67); Sorinola for re-entering the field of play to celebrate (90+7); Louza for a foul on Mannin (90+12); Fulton for kicking the ball away (90+16); Wood for pulling back Bayo (90+18).

Referee: Tim Robinson.