Arsenal were deserving winners for their brighter play though this was not a contest that teemed with quality. The culprit for Manchester United was Paul Pogba for a baffling lunge in the area on Hector Bellerín when the Spaniard was moving away from goal. That led to a penalty which Pierre-Emerick Aubameyang smashed home with just over 20 minutes remaining and United were left scrabbling for an equaliser they never secured.

It gave the Gunners a first Premier League victory at Old Trafford since 2006 and meant Ole Gunnar Solskjær’s 100th match in charge ended with a 24th reverse and lingering questions: this was Arsenal’s first three points for a month to move them on to 12 and ninth place but United have only seven from six outings and are in 15th.

Related: Ole Gunnar Solskjær fails to solve Manchester United's prickly problem

In this early season slump in home form they have also lost league games to Crystal Palace and Tottenham while drawing the other one with Chelsea.

A high-speed start featured Arsenal claiming the first corner – Willian swung this in from the left and Bruno Fernandes cleared. When the ball broke to Bukayo Saka his cross was met with a call to catch by David de Gea but Harry Maguire headed away in a moment of miscommunication.

At this juncture Mason Greenwood and Marcus Rashford interchanged positions on the flanks. This opened up space and so it was that Scott McTominay drove the ball in from the right, this rebounded to Fred, but his pass found only Gabriel.

The Arsenal counter was on and in quick-time Aubameyang was rolling in Saka for him to pull the trigger though United escaped.

The visitors had emerged as the side with greater muscle and intent. Mohamed Elneny, influential throughout, tapped possession to Willian who tapped on to Bellerín and he ran along the right and fired in a cross that sliced through United’s defence and almost found Aubameyang’s slide. Next, the diminutive Saka illustrated what Arsenal were about by shrugging off the far bigger McTominay.

Then, suddenly, United pounced. Aaron Wan-Bissaka fed Rashford and his curving pass beat Arsenal’s defence: Greenwood’s shot had Bernd Leno making a first save, the keeper using his legs. It was, though, a rare foray for Solskjaer’s team.

Pogba was soon hitting the ball away when Willian tried to sneak a free-kick in at the near post from the left after Wan-Bissaka fouled Saka.

Elneny in central midfield was the Arsenal hub, initiating play, often able to run with the ball and pinning United back, much to the disquiet of the bench. When Alexandre Lacazette produced an air shot right in front of De Gea it was merely the latest shaky moment in a half dominated by Arsenal.

Another was a Willian-Aubameyang one-two that had the Brazilian skimming an effort off De Gea’s bar. Factor in a previous Victor Lindelof intervention that, crucially, distracted Aubameyang, and Saka later spurning a header, and United were fortunate to be level at the interval.

Solskjær decided to allow the same players to rectify proceedings when the second half began and there was a snap in McTominay’s tackle on Aubameyang and in the ensuing Fernandes shot. It claimed a corner as, later, did some slick footwork from Greenwood that teed up a Wan-Bissaka attempt which was deflected away. Yet Arsenal still threatened with a lightning attack when Fred dallied. Lacazette took over and Aubameyang on receiving end beat De Gea but saw his shot go wide of a post.

At the other end there was a similar near-miss when Luke Shaw floated a free-kick to the far post and Maguire’s header threatened to go in or find the lurking Greenwood, but neither occurred.

Just after the hour Fred was replaced by Nemanja Matic, the Serb entering what had become a becalmed spectacle. The idea was surely to try and exert greater control via what was now a flatter three-man midfield with Fernandes ahead. More puzzling was what went through Pogba’s head when felling Bellerín in the contest’s pivotal moment. As, too, when Solskjær’s next changes were Edinson Cavani for Greenwood and Donny van de Beek for Fernandes, Pogba somehow surviving.

Arsenal had arrived with doubts about their creativity and departed having eased these. Instead, despite a late rally in which Matic drove at goal and Van de Beek’s effort was hit on to a post by Elneny via Leno’s head, it is United who are left pondering where precisely their league season is going. “We have to look within,” Maguire said.