Arsenal boss Wenger: Mertesacker will get better
The former Werder Bremen captain is still adjusting to the pace of the Premier League.
Wenger told arsenal.com: "I believe Mertesacker had to adjust to the pace and commitment of the English game but I feel that in every game he gets stronger. Let's not forget that we missed Koscielny as well. I personally feel that the defensive frailties we had recently were more down to other departments in the team than the defenders."