Manchester United were blown away 3-1 by an inspired Aston Villa on Unai Emery’s bow as boss, while Newcastle moved up to third with a 4-1 victory at Southampton.
Gabriel Magalhaes bundled in Bukayo Saka’s corner for the only goal at Stamford Bridge, but the slender margin of victory was the very least Arsenal deserved.
Chelsea offered barely anything going forward as they slipped to back-to-back Premier League defeats for the first time in two years.
“For such a young team, the maturity, the composure they showed, the resilience and courage to play how we wanted to play was phenomenal to do it against these kind of players,” said a proud Arsenal manager Mikel Arteta.
“Winning in this stadium is an extra thing, another step for this team to keep believing they can do it under pressure and against big opponents.”
Victory takes Arsenal back two points clear of Manchester City at the top of the table.
Chelsea remain in seventh, behind Brighton, who Graham Potter left in September to take charge of the Blues.
Liverpool had slipped down to 10th before kick-off at the Tottenham Hotspur Stadium after consecutive defeats to Nottingham Forest and Leeds.
But Mohamed Salah’s first-half double secured a first away league win of the season for Jurgen Klopp’s men.
The Egyptian coolly slotted home Darwin Nunez’s pass before pouncing on an error from Eric Dier.
Harry Kane pulled a goal back 20 minutes from time, but Spurs could not keep up their run of impressive late fightbacks to suffer a third defeat in four league games.
Emery’s dream start
United were unbeaten in nine games as the Red Devils appeared to be taking shape under Erik ten Hag.
But despite the lavish amounts spent to assemble the United squad, a lack of strength in depth was exposed with Antony, Jadon Sancho and Raphael Varane missing due to injury and Bruno Fernandes suspended.
Emery could not have asked for a better start to his time in charge of Villa as Leon Bailey smashed across David de Gea and Lucas Digne’s free-kick found the top corner inside 11 minutes.
“You have to be ready for the game, we were not,” said Ten Hag. “We lost the game at the start of the first half and start of the second half. That’s not acceptable.”
Luke Shaw’s strike that deflected off Jacob Ramsey into his own net gave the visitors hope just before half-time.
Villa, though, quickly restored their two-goal lead when Ramsey side-footed into the top corner on 49 minutes.
Cristiano Ronaldo captained United just weeks after being disciplined for refusing Ten Hag’s orders to come on as a substitute.
On another frustrating afternoon for Ronaldo, the five-time Ballon d’Or winner survived a VAR review for a red card after clashing with Tyrone Mings.
Newcastle’s sixth win in seven games took them above Tottenham into third.
Miguel Almiron continued his stunning form with a seventh goal in as many games to open the scoring in sodden conditions at St. Mary’s.
There was no way back for Ralph Hassenhuttl’s men once substitute Chris Wood found the far corner before Kieran Trippier set up Joe Willock to make it 3-0.
Romain Perraud pulled a goal back a minute from time, but Newcastle had the final word when Bruno Guimaraes curled into the bottom corner to leave the Saints still rooted in the relegation zone.
Michael Olise struck the winner for Crystal Palace deep into stoppage time as a 2-1 win at West Ham lifted the Eagles up to 10th.