The last time Arsenal failed to keep a cleansheet in the League or Champions League was our 0-0 draw with Middlesbrough in the Premier League on the 22nd of Oct.
However, recent reports have indicated that Mustafi is on his way back to full fitness from a hamstring injury after the player posted a video of him in the gym.
The Germany international has proven a superb signing for the Gunners since his summer transfer from Valencia, forming a rock-solid partnership with Laurent Koscielny at the back.
As well as that, Mustafi is yet to be on the losing side for Arsenal since he joined, with Arsenal losing two games and conceding four goals since his injury lay off.
— Shkodran Mustafi (@MustafiOfficial) December 19, 2016
Gabriel has been playing in his stead but the Brazilian looked the weakest link for Arsenal in defense and I’m sure every one would be waiting for Mustafi to return to action.