The league leaders hadn't lost in the Premier League since a 3-2 defeat at Manchester United in September, but they failed to match Everton for fight or commitment at Goodison Park. And Tarkowski's header was enough to consign Arsenal to a fourth defeat in their last five games away to Everton.
1. Arsenal fail physical test at Everton
Arsenal need to toughen up if they are to win the Premier League title, with this defeat highlighting some worrying failings for the Gunners.
Despite the obvious talent in Mikel Arteta's team, Everton showed that when a game is reduced to a battle of commitment and physical endurance, Arsenal can be found wanting.
Having played for Everton and experienced the Goodison Park crowd firsthand, Arteta will have known what awaited his side in this game. When times are tough, Everton revert to scrapping for points and getting the fans onside with robust tackles and lung-busting runs to track back.
The top teams know how to handle such an approach -- they stand up to the physical challenge and gain superiority with their additional quality. But Arsenal didn't do that and allowed Everton to grow in confidence with every 50-50 challenge. Ben White, Granit Xhaka and Gabriel Martinelli were the main culprits when it came to allowing their opponent to win the physical battle, but Martin Odegaard and Eddie Nketiah were also distracted by Everton's approach.
Everton's goal was an example of Arsenal being too easily beaten in a physical situation, with James Tarkowski more determined than anyone to win the header as he outmuscled Odegaard to nod home.
Previous Arsenal title challenges have faltered because the team has exposed their soft centre in challenging away games, so Arteta needs to ensure that this performance was a one-off.
2. Demanding Dyche has instant impact
Dyche has already had a galvanising effect on his Everton squad, despite only being officially appointed as manager last Monday. The Dyche effect was evident throughout this game.
The former Burnley boss was always a commanding presence on the touchline throughout his time at Turf Moor, but it appeared as though he had implemented emergency measures in his first game as Everton manager by taking his interaction with the players to a new level.
Dyche was constantly urging his players on from the technical area, both from a tactical perspective but also with motivational applause or thumbs-up gesture when a player had pressed with intent or produced a big tackle or pass.
His predecessor, Frank Lampard, was less demonstrative on the touchline and his team were too passive at times. That is unlikely to happen under Dyche and it was as if the new boss knew he had to be a visible, dominant presence to keep his players focused on the job.
Dyche has been unfairly pigeon-holed as a manager who plays basic, long-ball football. He is a smarter operator than he is given credit for and Everton will improve under him. But against Arsenal, it was a simple approach. A 4-5-1 formation, packed with big players, and a crowded defensive third.
Lampard was less inclined to play that way, but his teams were too open and Everton suffered for it. With Dyche they will be hard to beat, committed and now have a much better chance of avoiding relegation.
3. Title and relegation battle blown wide open
This result will have big implications at both ends of the table. Arsenal's first league defeat since September has given Manchester City the chance to claim top spot when they travel to the Emirates on Feb. 15, while Everton are now out of the bottom three after a first win since October.
When Dyche was appointed last week, only the most optimistic Everton fan -- and optimism has been thin on the ground here for a while -- would have backed the new boss to get anything from his first two games in charge. But having started off with a win against the league leaders, Dyche and Everton will travel to Anfield to face Liverpool on Feb. 13 with the belief that they can beat their Merseyside neighbours and climb even further from the drop zone.
After that, relegation rivals Leeds visit Goodison Park, so Everton have made the perfect start to what will be a crucial period for the club as they, once again, attempt to avoid relegation.
Yet while this was a huge morale-boost for Everton, it was a major blow for Arsenal and their nerve will now be well and truly tested in the weeks ahead. Champions City know that these dropped points mean that Arsenal can be knocked off top spot when the two clubs meet in the league for the first time this season in 10 days' time.
Best and worst performers
Dominic Calvert-Lewin -- Found some good positions, but needs to offer more threat in front of goal and use his attributes to greater effect.
Highlights and notable moments
James Tarkowski scores the first Everton goal of the Sean Dyche era.
Dyche made a real impact on his debut as manager.
2 - Sean Dyche is just the second manager to beat an opponent starting the day top in his first Premier League game in charge of a club, after Alan Curbishley's West Ham beat Man Utd in December 2006. Grit. pic.twitter.com/2mbKpcYalV— OptaJoe (@OptaJoe) February 4, 2023
After the match: What the players/managers said
Tarkowski speaking to BT Sport: "It has been tough for us and the fans and for all the staff in the club. Hopefully this is the turning point for the club, there is a lot of talent here. It's taken me a while, I need to score more. What a great time to do it and a great day. It's back to work on Monday and we crack on. We've lacked that little bit of grit at times and that's what the fans want. We've seen what it's all about today."
Arsenal manager Mikel Arteta on the game: "Well I think Everton were really good. We have to congratulate them first for how they've turned things around and I think they made it difficult to win the game because they were really efficient. From our side disappointment because we didn't get the result that we wanted and the performance doesn't reflect what we've been doing especially in two phases - one, when they were really direct and we struggled to control that type of game and get back to the game that we wanted to play, and then with the amount of open situations that we generated in the final third that has to finish with goals and clear cut chances more than we've done today."
Everton boss Sean Dyche: "The fans are going to be massive for us. I have been here [Goodison Park] when it has been rocking. It was rocking today. But we have to give the fans something. Of course I'm going to drive home and think what a great start but I'm not naive. We have to keep working and improving."
Key stats (provided by ESPN Stats & Information research)
- Via Opta: Arsenal have named the same starting XI in five consecutive Premier League matches for the first time since April-May 2015 (six games).
- Arsenal's previous four Premier League away games at Everton: 1-0 (L), 0-0 (D), 2-1 (L), 2-1 (L)
- Via Squawka: Arsenal faced 8 shots from Everton in the first-half. They haven't faced more from any other opponent in the first 45 this season.
- Tarkowski's last Premier League goal came under Dyche at Burnley, vs. Brighton on the first day of the 2012-22 season.
- Arsenal's last defeat (3-1 vs. Manchester United) came on Sept. 4, exactly five months ago.
Everton: The big one. A Merseyside derby against Liverpool on Feb. 13 at Anfield. Then a home game against Leeds on Feb. 18.
Arsenal: Two home games are up next as the Gunners host Brentford on Saturday Feb. 11 before a potentially key match in the Premier League title race against Manchester City on Feb. 15.