When Oumar Niasse was controversially sent off with well over an hour remaining, Marco Silva’s impeccable home record seemed in severe jeopardy.

By way of exacerbating the woes of the Hull manager Robert Madley’s debatable interpretation of Niasse’s challenge on M’Baye Niang looked the sort of decision on which relegations can hinge and tens of millions of pounds be forfeited.

Yet, as the crowd howled in anger and anguish, Silva’s players evidently resolved to remind everyone that appearances can be desperately deceptive. Inspired by, among others, the excellent Sam Clucas, they responded to such adversity to register another victory in their once seemingly hopeless fight against relegation.

This latest win here left Hull having collected an extraordinary 19 points from a possible 21 on East Yorkshire soil since Silva succeeded Mike Phelan in early January.

Thanks to second-half goals from Lazar Markovic and Clucas, Hull kept their noses in front of Swansea City, staying 17th at the end of an afternoon that started less than auspiciously for a manager who has not lost a home fixture in England, Greece or his native Portugal for more than three years.

“It’s a really important three points for us,” said Silva. “I don’t want to talk too much about the red card because I respect the referee’s job and I make mistakes sometimes too. But to play for 65 minutes with 10 men and win was fantastic from my players. I believe in these players and our work.”

Under the Portuguese’s tutelage Harry Maguire has turned into a much-admired young centre-half but before a minute was up his supposedly routine backpass to Eldin Jakupovic had morphed into a horribly mis-hit shot that whizzed inches wide of the far post.

Had that gone in it would have been Watford’s first away goal in the Premier League since January and they kicked off as if on a mission to correct that statistic. Andy Robertson may be coveted by Liverpool but Silva’s left-back initially found Nordin Amrabat quite a handful.

With the stream of long balls pumped forward also bothering the less than jet‑heeled Maguire and Andrea Ranocchia, Clucas and company struggled to get their passing game going. Then, just as it clicked into rhythm, Niasse saw red.

Hull City’s Oumar Niasse is shown a red card during the Premier League game against Watford. Photograph: Gareth Copley/Getty Images

Granted it was a little high, a little late, studs up and the striker’s boot appeared to fleetingly catch Niang below the knee but the striker’s challenge as they competed for the ball did not appear either reckless or totally out of control. It was certainly not a cynically calculated lunge and probably merited a yellow card.

Although the impact seemed minimal and accidental, what possibly swung Madley’s decision was that, before collapsing in apparent, writhing, agony, Niang unleashed an anguished, piercing scream so loud it could be heard in one of England’s highest press boxes.

When the winger finally rose to his feet one of his socks looked ripped but he was immediately able to run freely, albeit to a soundtrack of toxic, cacophonous boos every time he touched the ball.

“My feeling was he hadn’t touched him but maybe a yellow card,’ said Silva. “We’ll appeal the red card, we’re hoping to have it rescinded.”

Thanks to a superb save from Jakupovic that somehow kept out Sebastian Prödl’s header the scoreline remained goalless at half-time but Madley had not been forgiven and was jeered off at the interval.

It did not help his cause that, by now, Walter Mazzarri was also on his case, Watford’s manager having taken exception to a bad challenge on Niang from Ranocchia that the referee had turned a blind eye to. Maybe the visitors’ sometimes unappealing gamesmanship had coloured the judgment of an official who might also have awarded Silva’s side a first-half penalty.

Fuelled by righteous anger, Hull regrouped and, to wholesale astonishment, took the lead. No sooner had Jakupovic saved well from Étienne Capoue than they broke quickly with Kamil Grosicki sashaying down the right before crossing to the onrushing Lazar Markovic. Although the Liverpool loanee’s header bounced down on the goalline Markovic extended a boot and, crucially, lashed the ball in from point-blank range.

Shortly afterwards Clucas, a midfielder on Gareth Southgate’s England radar, took time out from helping hold things together in midfield to curve a free-kick wide of an upright.

It proved a preamble to a goal scored after Watford could only partially clear a corner. Having seamlessly chested the ball down, Clucas beat Heurelho Gomes with a sublime left-foot volley.

“We underestimated the danger from 10 men,” said Mazzarri. “It makes me really angry but Hull were really, really good. They concentrated very well. Congratulations to them.”