Per Mertesacker still believes Arsenal must prove title credentials

The Gunners moved to within two points of the Barclays Premier League summit with a 2-1 victory over fellow title hopefuls Manchester City on Monday night.
First-half goals from Theo Walcott and Olivier Giroud proved enough for Arsene Wenger’s side at the Emirates Stadium, despite Yaya Toure’s superb late strike for the visitors.