For only the second time this season, Arsenal failed to come through a difficult test and lost in the Premier League, as an inspired Everton dented their title push at a bouncing Goodison Park.
Enormous credit has to go to Sean Dyche and the Toffees, who produced comfortably their best performance of the season to suggest they are more than capable of quickly climbing the table under the former Burnley boss.
Despite pre-match protests against their ownership outside the ground, inside Everton fans got behind their team and new boss, and the players responded with an intensity and poise that was non-existent under Dyche's predecessor, Frank Lampard.
Their midfield three of Abdoulaye Doucoure, Amadou Onana and Idrissa Gueye were particularly impressive, snapping into tackles and pressing Arsenal into jittery mistakes. It was telling that Arsenal captain Martin Odegaard was hooked early, having failed to make an impression, while Oleksandr Zincheko, Granit Xhaka and Thomas Partey struggled to assert their usual control and class on the hosts.
Dominic Calvert-Lewin was also imperious, occupying William Saliba and Gabriel in a fine centre-forward display.
It was a measure of their dominance that the Toffees should have already been at least 1-0 up when James Tarkowski finally broke the deadlock on the hour - in true Dychian fashion.
Calvert-Lewin was twice inches away from scoring in the first half, while Doucoure also went close before Dyche's former Burnley charge shrugged off Martin Odegaard to head home a corner.
Arsenal were way off their usual pace in a display which felt more in keeping with the soft-centred Arsenal of last season, when they tended to shrink against fired-up sides in a heated atmospheres.
Arteta's side have not played this badly since the visit to Elland Road in October. On that occasion, they somehow came away with a 1-0 win but they were deservedly beaten here and rarely looked like scoring after Bukayo Saka had an effort cleared off the line in the first half.
No side, particularly one as youthful as Arteta's, can expect to go through the entire campaign without hiccups and the question is now whether Arsenal can respond to a rare setback, which felt as much down to Everton's new-manager bounce as their own shortcomings on the day.
After their first league defeat of the season, against Manchester United in September, Arsenal responded with an impressive 3-0 win at Brentford in their next match, part of a streak of eight consecutive victories in all competitions. A similar response is now needed.
TARKOWSKIIIII!! 🤩
— Football on BT Sport (@btsportfootball) February 4, 2023
The Sean Dyche era is up and running at Goodison Park as league leaders Arsenal go 1-0 down... 😳#EPL pic.twitter.com/cCOTIon2YQ
Coincidentally, up next for Arsenal is a visit from Thomas Frank's excellently drilled Brentford, who are among the hardest sides to beat in the top-flight and will have taken note of the way Everton bullied Gunners.
Then, after the Bees, Arsenal face an enormous test of their resolve and title credentials in the crunch mid-week game against Manchester City, in which the champions could now conceivably leapfrog the Gunners into top spot.
Arteta will urge his players not to panic and see the bigger picture but they now unquestionably face the biggest examination of their nerve. Arsenal's challenge in the next two games is to ensure this was just a blip, rather than the start of a more sustained collapse.
