De Gea is the best goalkeeper in the world and other things learned

Lingard struck on the counter-attack following fine work from Pogba, who was then shown a straight red card for a studs-up challenge on Hector Bellerin.

The midfielder’s offence carries an automatic three-match ban and rules Pogba out of next weekend’s Manchester derby.

The win saw second-placed United move five points behind rivals City, the Premier League leaders playing West Ham on Sunday, while Arsenal are seven points further adrift in fifth.

Here, we examine four things learned from the Emirates.

POGBA BAN DENTS TITLE CHANCES

A truly Jekyll and Hyde performance from Paul Pogba.

First, the good. When the Frenchman plays there is an instant verve and pace to United’s play.

His touches are quick and crisp, his passing likewise and the assist for Lingard’s second was a microcosm of the positive play he brings to United.

When put through on the angle, others would have shot and likely missed. Pogba, though, darted to the byline and then despite contact, maintained balance before poking a perfect pass for Lingard to tap home.

His importance to United is unquestionable. The rhythm of their play is dictated by the 24-year-old and that’s why his sending off triggered reverberations among the Old Trafford faithful ahead of next week’s Manchester derby.

Yes, they were a man down but United’s repression from attack to an ultra defensive approach when he left the field was indicative of how crucial he is.

Without him against City, a game which Mourinho’s men simply have to win to stay in touch at the top, their chances are diminished.

Corners of social media mocked his dismissal after he talked of a hope City suffer injuries to key players to give United an avenue back into the title race. But for United it takes just the loss of one man to hand the initiative to their city rivals.

DE GEA’S THE WORLD’S BEST KEEPER

There’s growing support for Barcelona stopper Marc-Andre ter Stegen’s claim to the throne as the world’s best goalkeeper but David De Gea showed again he won’t abdicate that title in the near future.

Ter Stegen has cut out the mistakes from early on in his Camp Nou career and has been virtually unbeatable this season.

A pillar of strength, his interventions at key times are one of the reasons why the Catalan giants sit top of La Liga.

But De Gea is simply otherworldly right now. In light of his display against Arsenal, it’s easy to jump to a hot take but his heroics at the Emirates Stadium was just an amplification of the qualities he’s shown all season.

If you read back through a text live commentary of United’s win, every update would read “De Gea saves”. He was 10/10, if a striker gets that rating for a hat-trick, then De Gea went beyond that.

The Spaniard made 14 stops against Arsenal – the joint-most by a keeper in the Premier League era.

And it was the complexity, dexterity and flexibility of the vast majority of those saves which impressed most.

He achieved quality and quantity to secure the three points, an absurd double save in the second half a testament to his title as the world’s best goalkeeper.

ARSENAL VICTIMS OF THEIR OWN DOWNFALL

Whether it was at the back, or up front, the Gunners shot themselves in the foot.

The game looked beyond the hosts inside the first 15 minutes after two dreadful defensive errors under the pressure of United’s high press.

Laurent Koscielny gifted United their opener when his awful pass was easily intercepted by Antonio Valencia. His pass inside to Pogba then saw four Arsenal players descend on the Frenchman with Valencia free on the right to take a touch and drill through Petr Cech’s legs.

And it got worse. Mustafi was robbed of possession trying to play the ball out from the back and credit to United, the path to goal was slick and surgical but it was still preventable.

When Arsenal finally fought their way back into the game, they then paid for their profligacy.

They had the chances to win this game by a margin and while De Gea was tremendous, the lack of conviction at times was infuriating.

Back to front, it just didn’t happen for Arsenal.

CROSSING THEIR HEARTS

Arsenal attempted 26 crosses against United which pointed to a lack of ideas, especially when the visitors went down to 10 men.

The vast majority of those were lazily hung in the air and the problem is they were employing the tactic against one of the strongest and tallest sides in the Premier League.

At one point, they had five international strikers on the pitch and yet the service to them was dire.

Pushing Iwobi out wide was the killer because Arsenal had no width and it led to the early meaningless crosses.