Arsenal seem to have finally found the missing piece of the defensive puzzle. The signing of Mustafi so far looks to have plugged the hole created by numerous average defenders that Arsenal have had over the last few years.
The injuries to Mertesacker and Gabriel may have seemed like a major problem at the time, but this could have been the best thing to happen to Arsenal this season. It meant that Wenger was forced to buy. Mustafi now seems like a bargain, a snippet of the price paid for John Stones by Manchester City.
The injuries also meant that we got to see the other new centre back Rob Holding in action. He looks to be the real deal, lets just hope he can develop the way we all think he can. We have seen a few games with Mustafi and Koscielny now at centre back and they seem to have the early signs of what looks like a complementary partnership.
As a back five, Arsenal can now boast to be up there with the top premiership sides. I would say only Spurs can match us in terms of defensive quality, although we shade it with our strength in depth.
Hector Bellerin, Petr Cech and Nacho Monreal now make up the rest of the pretty solid defence. Having the odd defensive lapse is what has cost Arsenal in the past, lets hope the guys at the back can keep up the good performances.