Mikel Arteta claimed his first win as Arsenal manager in impressive fashion as his side outplayed Manchester United to secure just a second victory in 16 games with a 2-0 win at the Emirates.
Nicolas Pepe and Sokratis Papastathopoulos struck before half-time to reward arguably Arsenal’s finest 45 minutes of the season so far.
The Gunners started the game three times as many points off the top four as the relegation zone, but a first home win in 87 days hauls Arteta’s men up to 10th and within four points of United in fifth.
There were signs of encouragement for Arsenal in Arteta’s home debut against Chelsea on Sunday when only a late collapse saw a 1-0 lead turn into a 2-1 defeat.
However, this time the hosts saw the game through as a dismal United performance raised fresh questions over their chances of finishing in the top four.
Ole Gunnar Solskjaer’s men were again shorn of Paul Pogba, who faces another few weeks on the sidelines due to an ongoing ankle injury.
United have grown used to coping without Pogba this season, but still struggle to create when denied the counter-attack and failed to recover after falling behind early on.
For the first time Arsenal started with all of Pepe, Pierre-Emerick Aubameyang, Alexandre Lacazette and Mesut Ozil together in attack and Arteta’s bold choice paid dividends eight minutes in.
Pepe scored just his second Premier League goal from open play since a £72 million move from Lille when he swept home Sead Kolasinac’s cross at the back post.
The Ivorian was suddenly brimming with confidence as he twisted and turned Luke Shaw before cross for Aubameyang to volley just over.
Lacazette then rolled Harry Maguire easily in a night to forget for the world’s most expensive defender before pulling his shot across goal.
David de Gea is another of United’s more experienced stars suffering an alarming dip in form and a poor clearance from the Spaniard offered another sight of goal to Pepe, whose long-range strike came back off the post.
Arsenal’s first half dominance was rewarded with a second goal before the half-time interval as De Gea could only palm Lacazette’s header from a corner back into the danger area and Sokratis pounced to fire into the roof of the net.
As the hosts’ energy levels dipped from a frantic first 45 minutes, United were allowed to dictate the game but did have the guile to make their possession count.
Andreas Pereira had the best chance to give United a lifeline but fired into the side-netting from Nemanja Matic’s clever reverse pass.
Mason Greenwood also forced Bernd Leno into a smart save, but United’s normal source of goals, Marcus Rashford and Anthony Martial, were kept in check as a much-maligned Arsenal defence kept just a fourth Premier League clean sheet this season.