Arsenal midfielder Francis Coquelin suffered a broken nose in the win over Everton.
It was the only sour note as the Gunners won 2-0 at The Emirates, bouncing back from a Champions League loss at home to Monaco.
Manager Arsene Wenger was unable to brush aside the injury after the win, admitting he was concerned as to when the midfielder would be back, and if he would need it operated on.
He told Arsenal's official website: "Yes [he has broken his nose]. I don’t know [how long he will be out], I hope not. I don’t know whether he will need surgery or not."
Coquelin has proved vital in recent weeks, filling a much needed void in defensive midfield for Arsenal.
The Gunners face QPR in midweek, and next Monday face a trip to Old Trafford to face Manchester United in the FA Cup.
The Frenchman could be back for both matches, albeit with a type of protective mask, or Wenger could rest him for the trip to Loftus Road and then risk him against United if cleared to.
His comments post-match however suggest he is taking nothing for granted, and Coquelin's fitness must be assessed before he is ruled available for either game.
Coquelin was one of the players who featured for Arsenal back in 2011 at Old Trafford as they were beaten 8-2, and will be keen to play and attempt to avenge that humiliation.
Midfielders Aaron Ramsey and Mathieu Flamini, both out with hamstring problems, are both listed as possible to return against QPR this week according to PremierInjuries.com