The Premier League season is barely four weeks old, yet Arsenal's latest title bid already faces a defining test.
Arsenal travel to fierce rivals Tottenham on Sunday without the suspended Declan Rice, the injured Mikel Merino and - most likely - skipper Martin Odegaard, who hurt his ankle on international duty on Monday.
It is the first test in a daunting eight-day stretch that also features trips to Atalanta and Manchester City and could derail Arsenal's season just as it is getting started.
First up are Tottenham. Arsenal arguably have the better side, even without their absent midfield trio. But the venom that accompanies this derby often changes the dynamic.
That was evident in the 3-2 victory over their rivals in April. David Raya - whose imperious start to this season has seen him nominated twice for save of the month - made a clanger which Cristian Romero capitalised on to blow the game wide open.
Martin Odegaard is likely to miss Arsenal's derby match against Tottenham due to injury
Odegaard hurt his ankle on international duty with Norway and he will undergo further tests
A poor run in December ultimately cost Arsenal last season as they were pipped to the title by City - who they face a week on Sunday - featuring losses to Aston Villa, West Ham and Fulham.
How the north London club navigates the next three matches with a growing injury list is crucial.
On Sunday, Arteta will have to get creative as he builds a makeshift midfield.
He knew last week he would be without Rice and Merino, because of suspension and a fractured shoulder respectively, but news of Odegaard's injury must have felt like a gut punch.
The captain was playing for Norway in their 2-1 Nations League victory over Austria on Monday when he left the field in tears after rolling an ankle.
Norway doctor Ola Sand told Norwegian newspaper Verdens Gang on Wednesday that the midfielder is likely to be out for at least three weeks.
He left the field in tears and may miss at least three weeks, Norway's doctor Ola Sand fears
The growing injury list means Mikel Arteta will have to get creative with his makeshift midfield
Mail Sport understands Odegaard is having further tests this week to reveal the full extent of the damage, after an initial scan on his return from international duty proved unclear due to the swelling around the joint.
The Gunners hope he won't be a long-term absentee but it's clear that he's a major doubt to face Spurs.
Rice is a big loss but has an experienced back-up in the form of Jorginho. Odegaard doesn't, and his work off the ball is just as crucial as his incisive passing.
The captain often leads the press of the opposition, particularly in the opening 10 minutes of matches and periods late on, which sets the tone and makes it difficult for defenders to play out from the back.
The highly regarded 17-year-old Ethan Nwaneri is in a similar mould, possessing creativity and dribbling ability in abundance, but it is unlikely Arteta will start him in such an important game.
Nwaneri impressed on Arsenal's US pre-season tour but has yet to feature this campaign, and Arteta is not one to take risks on youth. The youngster is instead expected to start against Bolton in the Carabao Cup third round in two weeks' time.
Declan Rice will also be a big loss but has a like-for-like replacement in the form of Jorginho
Kai Havertz could be brought back into midfield to replace Odegaard in a 4-3-3 set-up
Jorginho is earmarked to take Rice's place. The Italian is trusted for the big games by Arteta, having started against City twice and Liverpool in the league last season.
He is yet to feature this season but, with Merino out, he remains the only conventional central midfielder alongside Thomas Partey, who is in line to start his fourth consecutive match.
Arteta has a few options. Perhaps the most likely is bringing Kai Havertz back into midfield to replace Odegaard and keep the favoured 4-3-3 set-up. Havertz played in this position in the pre-season fixtures against Liverpool and Bayer Leverkusen, scoring in both games.
However, Havertz has excelled as a striker during the first three matches of the season, scoring against Brighton and Wolves. Moving him back to the middle of the park would limit his game and even stem the team's momentum up front, but times are desperate. This would mean Gabriel Jesus or Leandro Trossard playing as the false nine.
Another ploy would be to deploy two No 10s in a 4-2-2-2 formation - a tactic Arteta used in the 3-1 victory over Liverpool last February. Jorginho and Rice played as two holding midfielders that day.
Against Spurs, Arsenal could field Trossard and Havertz in front of Jorginho and Partey, with Gabriel Martinelli and Bukayo Saka occupying the two wide spots in attack.
New signing Raheem Sterling may make up part of the attacking three behind a lone striker
Gabriel Jesus is on hand to be used as a false nine or the out-and-out frontman against Spurs
A further possibility is to use a 4-2-3-1 formation, with Havertz, Saka and new signing Raheem Sterling making up the attacking midfield three, with Trossard or Jesus up top. This would be a way of incorporating Sterling, if Arteta wishes to throw him in against Arsenal's bitter rivals.
The final option is to bring in Oleksandr Zinchenko or Jurrien Timber alongside Partey and Jorginho as a midfield trio in a 4-3-3 set-up. Zinchenko has played in midfield for Ukraine. For Arsenal, his defensive frailties are often balanced against his ability to retain possession.
Timber is composed and was forced to cover space further up the pitch against Brighton after Rice's sending off. He played well in that cameo and is capable of stepping into that role.
There are plenty of avenues Arteta can go down. If Arsenal are to come out of this menacing eight-day period unscathed, it is essential that the Spaniard picks the correct one.