Watford were unable to extend their unbeaten Premier League run to a fifth game as Manchester United moved to within a point of the top four following their 2-0 victory at Old Trafford. But while there were positives for the Hornets to take back down the M6 and M1, they were also guilty of some sloppy mistakes and could have been out of the game by half-time on another day.

Although they survived the odd scare, the visitors held their own for the first 20 minutes but some loose passages of play and United visibly upping the ante saw the complexion of the game change as the Hornets found themselves subjected to a red-shirted barrage as the opening period wore on.

Heurelho Gomes twice had to excel to deny Paul Pogba and Zlatan Ibrahimovic and the visitors spurned other good openings during an impressive attacking spell which saw the visitors regularly over-loaded out wide. And they finally made their supremacy down the flanks count when Anthony Martial’s cut back was converted by Juan Mata.

The Hornets were still in the game at that stage but the points were effectively made safe on the hour when a slick and incisive move was smartly finished off by Martial.

Neutral observers might have expected United to go and add to their lead in the last half-hour and they had chances to do so. By the same token though, the Hornets enjoyed some of their best passages of the game and David De Gea had to react sharply to keep out a Troy Deeney snap-shot after Daryl Janmaat had fired a good chance over, while the United keeper had earlier been extended by a Mauro Zarate free-kick when the score was still 1-0.

Walter Mazzarri made just the one change from the side that made it back-to-back wins against Burnley and also opted to match up United’s 4-2-3-1 shape.

Miguel Britos returned at left-back with Valon Behrami, who had been a doubt in the build-up to the game, dropping to the bench. This meant Jose Holebas moved further forward to the left of an attacking three, with former United player Tom Cleverley and Etienne Capoue tasked with protecting the back four and providing a base in midfield.

Jose Mourinho’s team went into the game attempting to make it 16 Premier League games unbeaten but despite winning 3-0 at champions Leicester City last time out, the Portugese made a couple of changes with Daley Blind and Martial coming in for Marcos Rojo and Marcus Rashford.

The Hornets looked to start positively, moving into more of a 4-1-4-1 formation when they pushed forward, but it was the hosts who had the first semblance of an opening in the third minute when Pogba and Antonio Valencia linked up to neat effect on the right and the latter saw his cross deflected up into the air and into the penalty area. It still fell nicely for Ibrahimovic in space on the edge of the box, but the Swede didn’t connect properly with his attempted half-volley and the opportunity came to nothing.

Apart from dealing with one cross, Gomes had a relatively quiet start to the game, but he had to be on his toes in the eighth minute to nick a back pass away from the on-rushing Mata.

De Gea had his gloves warmed soon after for the first time when M’Baye Niang came in off the right and tried a curling shot after a Gomes clearance had broken for him. But the Hornets keeper was soon having to drop to his right to hold a shot from Henrikh Mkhitaryan after a Ibrahimovic pass had given the former Borussia Dortmund man the chance to advance.

Watford survived their first let off in the 13th minute when Cleverley gave the ball away in the centre of the park and Ander Herrera seized on it, finding Martial who cut in from the left and hit a shot that was deflected behind with Gomes helplessly wrong-footed.

The visitors had started decently though, were asking questions when they could get the ball in the final third and they had an opening in the 18th minute when Niang dummied a pass to Holebas. The AC Milan loanee was clattered by Valencia for his troubles, but referee Bobby Madley played a good advantage and Holebas advanced before hitting a searing left-footed shot which beat de Gea but swerved away from the far post at the last minute.

Back came United with Pogba capitalising on some space in front of him to progress before hitting a right-footed curler from 25 yards which Gomes parried behind with both hands. The Hornets dealt with that corner and soon after won one of their own which ended with Zarate trying a spectacular bicycle kick from the right angle of the area which De Gea held comfortably.

But United started to turn the screw as the half-hour approached and were soon to go close to taking the lead on several occasions.

First Pogba dropped a lovely ball over a Hornets defence which was trying to push out but Ibrahimovic timed his run to perfection, ghosting past Younes Kaboul, but United’s top scorer opted to take it first time on the volley and fired over.

It was then Gomes’ turn to come to the rescue, doing very well to react to keep out Pogba’s side-footed attempt on the run following a low Valencia cross from the right.

Herrera and Mkhitaryan then both wasted good shooting chances by firing over, the latter getting it horribly wrong, before Gomes made a superb reaction stop to deny Ibrahimovic from close range after Mata had become the latest United player to get in behind the visitors’ defence.

But the tide of red was now relentless and they finally made a chance count in the 32nd minute when Mkhitaryan slipped in Martial down the right side of the Hornets defence and his low cut back was side-footed home by Mata from just inside the six-yard box.

Watford were able to have a period of relative respite after going behind, including Gomes, but the keeper did have to drop sharply to get his body behind a well-struck Mkhitaryan shot two minutes before the break.

There was still time for the Hornets to be put very much on the back foot again when Martial ran directly at the defence down the centre of the pitch, but as he prepared to pull the trigger Sebastian Prodl was able to get in a vital challenge to keep the gap down to one goal at the interval.

The majority of the home side’s threat had come from out wide so it was no great surprise that Mazzarri decided to change things at the start of the second half, bringing on Janmaat for Britos with Holebas reverting to a role in the back four.

Craig Cathcart had been having a tough time of it dealing with Martial on the right flank and the young Frenchman was it again within two minutes of the restart, running at the Northern Ireland international before fizzing a low shot across the face of goal.

Watford were still in the game though, and eight minutes after the restart De Gea had to move sharply to his right to parry a well-struck Zarate free-kick from 25 yards out left of centre.

That could have been 1-1 but as the hour mark approached United doubled their lead in devastatingly simplistic fashion.

Capoue lost possession in the middle of the pitch to Herrera, Pogba slipped a pass forward to Mkhitarayan, who found Ibrahimovic and he timed his forward ball to perfection as Martial stayed onside before breaking into the area. The young striker was briefly held up as he came inside but instead of looking for a teammate, he whipped a low finish inside the unsighted Gomes’ near post to make it 2-0.

Gomes made his latest save to keep out Ibrahimovic’s strike from the edge of the area soon after, but then the visitors had an opportunity when Niang got in behind Blind to the byline but nobody in a white shirt was there to get on the end of his ball across the six-yard box.

Watford were slowly beginning to have some more joy going forward and when Niang beat Blind down the right again, he sent over another fine cross which Janmaat saw coming all the way, but he got under his attempted angled first-time finish and fired over.

Mourinho made his first change in the 73rd minute as Marouane Fellaini came on for goalscorer Mata but then Kaboul picked out Deeney with a diagonal ball into the area and after bringing it down at the second attempt, the Hornets top scorer almost caught De Gea out with a snap shot.

A promising afternoon for Zarate was ended when he was replaced by Stefano Okaka with 16 minutes to go, but Watford continued to be the side that was attacking the more with Janmaat the next to try his luck with a shot from the edge of the area that went wide of the near post.

Rashford replaced Martial for the final ten minutes and then Isaac Success came on for Cathcart, but in between times Ibrahimovic had missed a gilt-edged chance to make it 3-0, getting his timing so wrong that he sent Mkhitaryan’s cross back in the direction it came from within the six-yard box.

It looked like Madley would go the whole game without showing a yellow card, but in injury time he did caution Valencioa for a foul on Holebas as United saw out the win with relative comfort in the final stages.

Manchester United: De Gea; Valencia, Bailly, Smalling, Blind; Mata (Fellaini 73), Herrera; Mkhitaryan (Lingard 89), Pogba, Martial (Rashford 80); Ibrahimovic. Not used: Romero, Rooney, Carrick, Darmian.

Watford: Gomes; Cathcart (Success 83), Kaboul, Prodl, Britos (Janmaat 46); Cleverley, Capoue; Niang, Zarate (Okaka 74), Holebas; Deeney. Not used: Arlauskis, Mariappa, Behrami, Doucoure.

Bookings: Valencia for a foul on Holebas (90).

Attendance: 75,301.

Referee: Bobby Madley.