Arsenal were given a fresh injury concern on Saturday after Rob Holding was injured in the warm-up before the 1-0 defeat to Manchester City.
The centre-back was named in Mikel Arteta's starting lineup at the Etihad, but he was pulled out just before kick-off after sustaining a muscle injury.
Ultimately, the master had just a bit too much for his former apprentice on Saturday as Raheem Sterling's first-half opener gave Pep Guardiola's Citizens the three points.
But there will be heartening elements of the performance for the Gunners boss, as they continue their transition to being a much less flaky team in big games.
The game saw the debut of Thomas Partey, who came on for Granit Xhaka in the final 10 minutes, and Arsenal fans will be eager to see more from the deadline day signing as attention turns to the Europa League.
Arsenal face a trip to Austria on Thursday to take on Rapid Wien before returning to Premier League action on October 25 against Leicester City.
Arteta has plenty of injury concerns to wrestle with, and he will be eager for good news on Holding's issue early this week.
Here is a round-up of all the very latest Arsenal team news ahead of the trip to Austria.
Rob Holding
The centre-back was named in the starting XI alongside Gabriel Magalhaes in the heart of the Arsenal defence, but the 25-year-old was injured in the warm-up.
David Luiz was drafted in to replace Holding at the last minute after the former England under-21 defender tweaked his hamstring.
"We don’t know (how bad it is) yet," Arteta said after the game. "But it was bad enough to make the decision to get Rob out of the game and to get David in."
There should be more clarity on Holding's fitness ahead of Thursday's Europa League clash with Rapid Wien.
Ainsley Maitland-Niles
The Arsenal midfielder made his first start for England in their 1-0 defeat to Denmark on Wednesday evening.
Fielded in a now familiar left wing-back role, Maitland-Niles was then withdrawn after 36 minutes for Tyrone Mings.
However, this was not an injury problem and the Arsenal academy graduate was merely sacrificed in a tactical reshuffle after Harry Maguire's red card.
The 23-year-old was an unused substitute at the Etihad.
Pierre-Emerick Aubameyang
Arsenal captain Pierre-Emerick Aubameyang did not report for international duty with Gabon.
The 31-year-old was initially called up for the weekend's clash against Benin.
However, it has since been revealed that he sustained a minor ankle problem during the Gunners' 2-1 win over Sheffield United and had to withdraw from the squad.
"After the withdrawal of Mario Lemina, another executive, Pierre-Emerick Aubameyang, will not be present to face Benin in a friendly match on October 11 in Lisbon," a statement read.
According to coach Patrice Neveu: "Aubameyang suffers from a small sprained ankle, contracted on Sunday, during the Premier League match against Sheffield [United].
"The Arsenal doctor sent me a certificate indicating his unavailability. He is in care for a week."
In the end, there were no worries for Arsenal as Aubameyang played the full 90 minutes against Man City, and he will be a crucial figure in a busy week for the club as they begin their Europa League campaign before hosting Leicester City in the Premier League on October 25.
Kieran Tierney
Arsenal defender Kieran Tierney was advised to self-isolate for 14 days after coming into close contact with a COVID-positive teammate during his time away on international duty with Scotland.
Southampton ace Stuart Armstrong was diagnosed with coronavirus, the Scottish FA confirmed last week, and Tierney's alleged close proximity to the midfielder means he was advised to begin a two week period of self-isolation.
Tierney's isolation appeared to rule him out of Arsenal's Premier League game against Manchester City.
But the Gunners released a statement last Wednesday, to clarify their position.
Arsenal said: “Our medical team have confirmed that Kieran was socially distant at all times from the player who tested positive and has broken no rules regarding Covid-19 protocols.
"We are currently seeking further advice and clarification of the details.”
On Thursday, Arteta issued a further update on the prospect of the left-back featuring against City, insisting he hopes to have him available.
The Spaniard said: "This is getting very complicated when we are sending players abroad and obviously you lose control, some authorities have different regulations to the actual ones in the Premier League.
"We are still having some discussions with the authorities and hopefully we will know more this afternoon."
Ultimately, Tierney was allowed to play and saw out the full 90 minutes at the Etihad.
Mesut Ozil
Mesut Ozil has been left out of all of Arsenal's matchday squads so far.
It's understood the move is down to tactics and Arteta's choice, rather than the German international having any sort of injury though.
That trend continued on Saturday as Ozil stayed at home, and his chances of forcing his way back into the team look slim.
Pablo Mari
The Spanish defender remains sidelined with an injury to his left ankle. He picked up the problem - which saw damage to his ankle ligaments - in the game with City back on June 17 - the first game back following the lockdown period.
He is continuing outside running and undergoing a strengthening programme as he makes a return to full fitness.
Mari has also been doing some light ball work as part of his recovery. The plan was for him to return to full training this week.
The City game came too soon for him, however, and a more likely return could be in the Europa League game away to Rapid Vienna on Thursday.
Sokratis
The defender is yet to play for Arsenal this season.
The Greek has been tipped to leave the club this summer, with Napoli and Paris Saint-German linked with a move.
He remains with the club and is fit so was in contention to be in the squad to take on City, but he was left at home.
Calum Chambers
The defender has been out with a serious knee injury since the end of last December in the home defeat by Chelsea.
He had been expected to return to action towards the end of the calendar year but that could now be sooner.
Arsenal say Chambers is progressing well in his recovery and is now taking part in first-team training sessions.
The former Southampton player is aiming to be back in full training after the international break so is likely to be ready to play at the end of the month, if not sooner.
Shkodran Mustafi
The German was enjoying something of a renaissance under Arteta and had been particularly impressive in the FA Cup semi-final win over Manchester City last season, only to suffer a hamstring injury in its closing minutes.
Mustafi underwent a minor medical procedure in the immediate aftermath of the injury, which Arteta confirmed was a pull to the "tendon of the bone of his hamstring".
The defender is said to be progressing well and he is now featuring in first-team training.
Like Chambers, he is set to return to full training after the international break.
Gabriel Martinelli
Arsenal have received a huge fitness boost with Gabriel Martinelli making progress on his return.
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Martinelli was initially ruled out until the end of the year with a serious knee injury.
But the forward now says he could be back in training for Arsenal soon after making rapid progress in his rehabilitation.
“I’m feeling very well, I’m regaining confidence and I can feel my knee is better,” he told the Arsenal website.
“After an injury like this you are kind of scared to force the knee again but the past couple of weeks it has been fine and soon I can start training with the ball."