United cut Manchester City’s lead at the top of the Premier League table to five points with a 3-1 win over Arsenal. Here are five things we learned from the match at the Emirates Stadium as The Red Devils finally secured an away win over a top six rival.

3-5-2 is United’s best formation

José Mourinho has generally favoured a four-man defence throughout his career and United’s previous experiments with the 3-5-2 system under Louis van Gaal were a disaster.

However, currently the formation gives Romelu Lukaku much greater support, offers pace in the shape of Anthony Martial and Jesse Lingard, as well as freeing up Ashley Young and Antonio Valencia licence to bomb forward and offer genuine width, as evidenced by the Ecuadorian’s opening goal.

It is undoubtedly United’s best shape and you can see how players such as Marcus Rashford, Juan Mata and Zlatan Ibrahimović would fit in when the time comes to rotate the squad.

Variations on three at the back are often seen as defensive but Chelsea showed last season that it is a system that can deal with myriad threats and bring about success over the course of the season. Mourinho should deploy it every week.

Jesse Lingard is underrated

There have been times in his United career when Lingard has frustrated many fans, myself included, but he has made a telling contribution this week, with a match-winning double here to go with his sensational goal at Watford on Tuesday.

He harried the Arsenal backline throughout, was tactically diligent, offered pace on the break and took his opening goal exceptionally well.

This was always a game in which he would have space to run into and as the member of United’s frontline offered the freest role here, he took full advantage, popping up all over the park and never letting his energy drop.

He isn’t the biggest name in the United squad but the years of success under Alex Ferguson were built on squad players who did not disappoint in the big games and Lingard – with his penchant for cup final goals as well – looks like another in the same mould.

José’s instincts are still to park the bus

It was clear from the two quick-fire early goals that United’s approach here was more positive than we have become used to seeing in big away games under José Mourinho.

However, as soon as Arsene Wenger took the bold move of replacing the injured Shkodran Mustafi with Alex Iwobi, the former Chelsea manager pulled Martial out to the left flank, isolating Lukaku in something of a 5-4-1 formation.

You could argue that it’s only clever to protect what you have when you burst into an early 2-0 lead and Lingard’s goal to seal the win bears that out on this occasion.

However, the approach ceded lots of ground to Arsenal and let them get far too close to the United goal for comfort – Mourinho should realise that sometimes attack is the best form of defence for this United side.

David de Gea is the world’s best goalkeeper

We’re hardly learning this for the first time, as De Gea has saved United on countless occasions over the past five years but he was magnificent again here.

As mentioned above, United tried to soak up pressure but were powerless to stop Arsenal bursting through at times and you could easily argue that they would have lost this game without the mercurial Spaniard’s interventions.

He produced outstanding saves to stop Alexis Sanchez, Alexandre Lacazette and even a goalbound deflection off Romelu Lukaku’s standing foot.

He was so good, yet again, that I’ll even forgive him for the shocking top-knot he is currently in the process of growing out.

United suffer badly when Nemanja Matić isn’t fully fit

This was a pulsating end-to-end affair, and that was largely due to the lack of protection offered to both defences by a holding midfield player.

This is nothing new or surprising from Arsenal, who were chasing the game almost from the start and have struggled in this position for years, but Nemanja Matić was bought this summer to give United steel and experience in that role.

It was clear that the Serb was still labouring with the injury that forced him off at Vicarage Road in midweek as he struggled with the pace of the game and Arsenal’s intricate attacking play.

My criticism of Mourinho’s overly defensive tactics at 2-0 should be mitigated by the fact that his main holding midfield player was very clearly not at full speed and this certainly went some way to allowing Arsenal to boss the game as much as they did.