Arsenal ended a run of 29 games without a win at a big-six side as Pierre-Emerick Aubameyang's second-half penalty gave them a 1-0 victory at Manchester United.
In Ole Gunnar Solskjaer's 100th game in charge, Manchester United's much talked about diamond midfield struggled to deal with Arsenal's energy, and the visitors had the better of the chances as Willian hit the bar and Bukayo Saka headed over unmarked.
Aubameyang curled an effort just wide after the break, but he got another chance from 12 yards after Paul Pogba had fouled Hector Bellerin in the box, and the Gabon striker duly converted (69) to end the Gunners' hoodoo, which had lasted since 2015.
Arsenal's deserved win moves them into the top half, but Manchester United, who hit the post via a double Mohamed Elneny and Bernd Leno deflection late on, have just seven points from six games.
Man Utd: De Gea (5), Wan-Bissaka (4), Lindelof (6), Maguire (6), Shaw (6), Fred (4), McTominay (5), Pogba (5), Fernandes (5), Greenwood (5), Rashford (5)
Subs: Matic (6), Cavani (5), Van de Beek (7)
Arsenal: Leno (8), Holding (8), Gabriel (9), Tierney (7), Bellerin (8), Elneny (8), Partey (9), Saka (7), Willian (7), Lacazette (8), Aubameyang (7)
Subs: Nketiah (6), Maitland-Niles (NA), Mustafi (NA)
Man of the match: Thomas Partey
How Arsenal's 'perfect' game plan stunted United
This fixture has so often showcased first versus second in the Premier League, but with both sides starting the game in the bottom half, the aim was more to kick-start indifferent starts to the season.
Arsenal's press was led by summer signing Thomas Partey, "the best player on the pitch" according to Sky Sports' Jamie Redknapp, but it failed to yield a goal in the opening hour.
Willian hit the bar from the edge of the box following a nice one-two with Aubameyang, but the best chance fell to Saka, who headed over unmarked from Bellerin's cross after Victor Lindelof and Aaron Wan-Bissaka simply failed to challenge.
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United were flat, and mustered up just one shot in the first half, their fewest in a Premier League home game since October 2015, and had just three touches in the Arsenal box, their fewest since December 2017.
Arsenal were edging what was at times a low-quality game of chess as United altered the midfield diamond, and after Aubameyang curled just wide from an Arsenal break, the striker had a clearer sight of goal from the penalty spot after Pogba's clumsy clip on Bellerin just inside the box.
Bellerin got goal-side of Pogba to draw the foul, one of referee Mike Dean's easier decisions, and Aubameyang made no mistake, sending David de Gea the wrong way.
United's inevitable spell of pressure came, but sub Donny van de Beek's double-deflected cross, off Elneny, then Leno, then the near post, was the closest they came in the entire game.
Arsenal's win was thoroughly deserved as Mikel Arteta "set them up perfectly", according to Sky Sports' Gary Neville, an apt example of the Gunners' more conservative and considered approach under the Spaniard as they hold the best defensive record in the top flight.
Paul Pogba started for Manchester United as Ole Gunnar Solskjaer made two changes; Mason Greenwood also came in as Juan Mata and Dan James dropped out.
Rob Holding's inclusion was a surprise given his muscle injury suffered in the warm-up at Man City a fortnight ago, but he came in alongside Mohamed Elneny and Thomas Partey. Dani Ceballos and Granit Xhaka dropped to the bench, with David Luiz out injured.
But for Solskjaer on his century of games, questions remain over consistency and how best to use United's midfield personnel after another sub-par showing from Pogba.
Roy Keane on Sky Sports:
"Where do you want me to start? A lack of energy, of enthusiasm, and a real lack of quality. That really concerned me. No quality, no composure.
"Some of the performances were really poor. Have they turned a corner? It's the longest corner ever. I am just not convinced by these players.
"I looked at Rashford closely today. His body language was shocking. Shrugging his shoulders when things didn't go his way? You roll your sleeves up when you play for Manchester United. I don't see any leaders out there. I am really, really worried about Manchester United now.
"A real lack of quality. There's a long way back for this club. I don't see men out there. I don't see guys who you want to be in the trenches with, guys you would trust."
Nev on United midfield: More problems than solutions
Sky Sports' Gary Neville:
"There are more problems than solutions. You have six midfield players at the club: Nemanja Matic, Fred, Scott McTominay, Bruno Fernandes, Donny van de Beek and Paul Pogba and you've somehow got to get them into a system, which is forcing Ole to play a diamond.
"I think there was an element today of him thinking he could just put four players in that diamond and it would work after what happened in midweek but McTominay on the right-hand side wasn't working after five minutes.
"You have to be comfortable moving out into that wide area; Wan-Bissaka's already a bit awkward on the ball at right-back so you need someone to balance it and the balance on the right is a real problem for United. When Greenwood went off it was even worse. They wanted Jadon Sancho obviously to play on that side and it looks like a real bad error in not getting that position recruited.
"Changing systems, players - having plenty in one position and not enough in others - is a real problem. Manchester United's full-backs aren't the best attacking full-backs in the world - Luke Shaw's ok going forward; he gives a bit of balance - but you're playing a diamond and your width's coming from players who don't really play that position well in terms of being high and wide. It's all looking a bit scruffy and towards the end, I'm not sure what shape United were playing."
Pogba holds his hands up
Manchester United midfielder Paul Pogba on BBC:
"We know it's a poor performance. Myself, I cannot give a foul away like this. I thought I would touch the ball but I didn't. [I] cost us the goal today with the penalty.
"We have to do better, the team, myself, it starts with me. I felt like I touched him a bit, I knew I was in the box, I shouldn't have given a penalty away like that.
"Maybe I was a bit out of breath, it made me do this stupid mistake. I will learn from that, I'm not the best defensively in the box, I can work on that."
Roy Keane on Sky Sports:
"He was outstanding. He's obviously no mug having played in big games. When you watch a player live that's when you can judge a player and the more I look at him the more I wish he was in the United midfield. He's big, strong and aggressive - and he can pass it forward. He can deal with the ball.
⭐️ Thomas Partey's contribution for @Arsenal today— Sky Sports Statto (@SkySportsStatto) November 1, 2020
Completed 53/57 passes
11 x possession gained (most in match)
Won 10 duels - most by an Arsenal player in a PL game this season
3 dribbles completed
1 shot on target pic.twitter.com/5qBfTDBuOa
"I had my battles with Vieira and I think this kid has got a chance of matching what Patrick used to do."
What the managers said...
Man Utd boss Ole Gunnar Solskjaer: "We never turned up first half, that intensity, tempo wasn't there. Their shape was better than us. Second half it didn't look like they were going to score, apart from the pen. We played better second half, but we have to turn up with more intensity. We weren't at the races.
"We need to get points on the board. Last season we didn't get that third win until the 10th game I think. Now we're on six games, with only two wins, so we need to focus on next week at Everton."
On the penalty: "Stay on your feet there, the boy is on his way out of the box, and Paul knows that it's a soft penalty to give away."
Arsenal boss Mikel Arteta: "I didn't want to tell the players we didn't win here in 14 years, I kept it quiet.
"The team you saw tonight is where we're starting to be. I am proud, to show the personality to play against this team at Old Trafford, I'm delighted with the win.
"They played a really tricky formation, the diamond, and I think we were really aggressive. They played two or three different formations, but I think we did really well.
"We needed this win. We shouldn't have lost against Man City, and definitely should have lost against Leicester. Having played at Anfield, Etihad and here in the first seven games is a big ask."
- Manchester United have lost at home against Arsenal in the Premier League for the first time since September 2006, with the Gunners ending the Red Devils 13-game unbeaten run (W8 D5).
- Only Chelsea (18) have won more Premier League games against Manchester United than Arsenal, with this their 16th victory against United.
- Manchester United have taken just seven points from their six Premier League games this season, their lowest tally at this stage since David Moyes' short stint at the helm in 2013-14 (7), a campaign in which they went on to finish 7th.
- Manchester United have failed to win any of their opening four top-flight games at Old Trafford for the first time since 1972-73, a campaign in which they finished 18th.
- Manchester United have conceded five penalties in their last seven Premier League home games; the previous five penalties they had conceded at Old Trafford in the competition came over a period of 101 games.
- Paul Pogba has conceded three penalties in the Premier League under Ole Gunnar Solskjaer, while no other Manchester United player has conceded more than one.
Manchester United go to Istanbul Buyuksehir in the Champions League at 5.55pm on Wednesday, before going to Everton at 12.30pm in the Premier League on Saturday.
Arsenal host Molde in the Europa League on Thursday at 8pm, and then welcome Aston Villa to the Emirates at 7.15pm on Sunday, live on Sky Sports Box Office.