Another concern for Arsenal: Kai Havertz suffers a setback in his recovery from a knee issue

According to The Daily Mail, his knee ‘flared up’ again after he returned from injury, while it has since been revealed that the attacker was ‘far from full fitness’ when included on the bench for the match against Villa.

Concerns remain inside the club that if his knee “continues to flare up, they could have long-term ramifications that could see the club forced to settle for prolonged management of his game time, rather than having him fully available for every match”. 

Speaking in December, when the Gunners had the most injuries in the league, Arteta said, when asked if training methods were to blame: "No, because we don't have time to train. Today we've done 20 minutes, so surely it's not because we over-trained the players.

"But obviously when you are missing players, you are loading other players and there is a consequence to that, and it's a really dangerous circle.

"You have to separate the kind of injuries. Some of them have been long-term and some have been acute injuries. It's something that we are constantly looking at.

"We have played a lot of games with a lot of players missing and that puts a lot of stress, and then you get more injuries."

Owing to his work rate and tactical flexibility, Havertz remains an important part of Arsenal’s system. The former Chelsea man showed his potential impact with a brief but impressive cameo against Portsmouth in the FA Cup.

That said, the German forward’s absence may force the club’s recruitment staff to evaluate the need for extra attacking options before the winter window closes.

Arsenal welcome Manchester United to the Emirates on Sunday for the reverse of the fixture that saw Havertz pick up his injury. Mikel Arteta will take encouragement from the fact that his alternative forward options, Gabriel Jesus and Viktor Gyokeres, both found the net in Tuesday’s victory. A win would further solidify Arsenal’s lead at the top.

Alongside Bayern Munich, Arsenal are certain to feature in the Champions League knockout stage. They are the only team this season to have won all of their matches in the league phase.