Story of the match
Having lost 12 of their 14 Premier League games against the visitors coming into today, Watford knew history and form were against them with just two points separating the hosts from Burnley in the relegation zone.
Watford Head coach, Claudio Ranieri was buoyed ahead of kick-off by midfielder Ozan Tufan passing a late fitness test but he was confined to the bench as Adam Masina and Imran Louza came into the starting-line for Francisco Sierralta and Juraj Kucka, with Louza making just his second Premier League start in a 4-2-3-1 formation for the Hornets.
However, each game already feels like a must-win for Solskjær.
Already five points adrift of the Champions League places with just one win in the previous seven league games Solskjær found himself without Paul Pogba, Raphael Varane and Edison Cavani as he made three changes from two weeks ago with Marcus Rashford, Jadon Sancho and Nemanja Matic coming into the starting line-up.
Under the floodlights and cheered on by a raucous home crowd, Watford started the stronger and thought they were ahead inside ten minutes.
Jonathan Moss duly pointed to the spot as the home crowd called for a sending off but VAR saved McTominary’s blushes and soon, Manchester United’s.
VAR quickly brought the pandemonium under control as Femenia was found to have encroached in the box during the penalty and, therefore, requiring a re-take.
Four minutes after the penalty was awarded, Sarr stepped up again and once more put a tame penalty to De Gea’s left, this time pushed away for a corner.
Whilst a golden opportunity had twice gone begging, it could not quash Watford’s endeavour as they continued to dominate the opening exchanges.
In the 15 minutes to follow, Watford created further chances through Emmanuel Dennis, Sarr and King but United’s defence held strong as their midfield was overrun by 4-2-3-1 formation.
Sarr enjoyed the best of the chances in the 27th minute as he went one-on-one with De Gea but summed up his recent form as missed the ball completely from 10 yards.
The home crowd were growing restless with the amount of missed chances but only had to wait one more minute before erupting.
Dennis picked up the ball on the left side of the box and fired in a low cross to King six yards out. Reacting instinctively, King diverted the ball goalwards and the pace on the ball meant there was nothing De Gea could do as it nestled in the net.
Manchester United registered their first chance in the 31st minute as Rashford drew an athletic save by Ben Foster but it provided only brief respite as the Hornets swarmed forward once more.
In the 37th minute, Dennis broke the offside trap to create a one-on-one with De Gea but the Watford striker couldn’t sort his feet out as Harry Maguire recovered to deflect the ball out for a corner.
Three minutes later and the Hornets again went close as King sent a bullet header at De Gea from 8 yards before Moussa Sissoko drilled his volley wide from the edge of the box.
Watford finally extended their lead on the stroke of half-time.
Jadon Sancho and Maguire left Sarr with the freedom of the box as the Senegalese striker made a mends for his penalty misses by firing a low finish across De Gea and into the bottom corner.
It proved to be the end of a breathless half of football and it was the last action for McTominary and Rashford as they were replaced by Anthony Martial and Donny Van De Beek at half-time.
As the game restarted, Van De Beek was immediately into the thick of the action.
With the second half just five minutes old, Sancho fired a deep cross into Cristiano Ronaldo at the back post who sent his header back across goal to Van De Beek who tapped in from six yards for only his second goal for the club.
With United sensing cracks in the Watford defence, Van De Beek starting to dictate the tempo and opened up the defence again seven minutes later as Ronaldo latched onto his through-ball but saw his effort tipped over brilliantly by Foster to keep the Hornets a goal ahead.
Ranieri reacted to the change in momentum with the introduction of William Troost-Ekong and Cucho Hernandez for Nicolas Nkoulou and Sarr respectively but it was Cleverley who swung the pendulum back in the favour of the hosts.
In the 69th minute, with Tom Cleverley leading a full-pitch press, he capitalised on a loose touch by Maguire to draw a foul and the Manchester United’s second yellow card.
The visitors were left with 10 men for the remaining 20 minutes but continued to push for the equaliser and thought they had it in the 77th minute.
Quick feet from Van De Beek saw Ronaldo pick the ball up inside the box and dance around the Watford defence before tapping in but the Portuguese international had come from an offside position and the goal was duly ruled out.
A minute later and it was Fernandes' turn to fire over from the edge of the box as United piled on the pressure.
With United pushing forward, Watford sought to capitalise on the gaps and finished the game off in added time.
With the visitors committing players forward, Dennis picked up the ball and found substitute, Joao Pedro in the box. With a tight angle, the young Brazilian squeezed the ball passed De Gea at his near post for Watford’s third but the Hornets were not finished there.
In the final action of the game, Dennis pinched the ball off the toes of King and fired across De Gea for Watford’s fourth to send an already jubilant home crowd delirious.
It was a frantic end to a breathless match as United succumbed to another embarrassing defeat under Solskjær but on today’s performance, you have to ask how long his reign will continue.
For Watford and Ranieri, however, it is all smiles as the Hornets moved into 16th with their fourth victory of the season.
Takeaways from the match
Bark and signs of bite in attack
No team has failed to score in more different Premier League matches than Watford this season (7) and for periods of this game, fans might have wondered if it would be the same old story for the forward line.
With missed penalties and chances a-plenty, the Hornets evidently do not struggle in creating openings, just finishing them. Excluding the 'traditional six' in the Premier League, King is second on the list for most chances created per 90 minutes with over 2 and Emmanuel Dennis not far behind.
However, today was another story.
With Dennis and King replicating their dynamic five-star performance against Everton back in October, Watford fans will be hoping the goals keep on raining at Vicarage Road.
Flickers of hope in defence
Watford have conceded at least once in each of their last 22 Premier League games - it's their longest ever run without a clean sheet in the top-flight but they are starting to show signs of stability with the October arrival of Nicolas Nkoulou in central defence.
Today Nkoulou stuck to his task like duck to water as he shadowed Ronaldo and Fernandes and limited their chances until his withdrawal in the 63rd minute. After the game, Ranieri suggested the withdrawal was due to fatigue rather than through injury.
Without Nkoulou, the defensive deficiencies of Watford were again on full display as Craig Cathcart and substitute William Troost-Ekong stepped off the opposition and allowed Van De Beek and Ronaldo space and time in the box but the Hornets midfield provided able support to keep United to a single goal.
Watford fans won’t often see Cleverley top the charts for goals or assists but today his contribution in a midfield 5 for the Hornets was integral to victory.
With the most tackles for Watford in the first half and the most yards covered, Cleverley was pivotal to disrupting United attacks and initiating Watford counters.
Alongside Sissoko in the holding midfielder role, Cleverley pushed forward with confidence and his pressure on the Manchester United defence was critical in the second half as he caught Maguire out to draw a foul and second yellow card for the England captain.
The sending off took the sting out of United’s attacks, particularly from set-pieces and whilst there were moments for Ronaldo and co. to steal the show, Watford were able to hold on for a memorable victory.