The Germany playmaker became Arsenal's record signing when he joined the Gunners from Real Madrid on transfer deadline day last summer. His debut campaign has been a success - Ozil tops the first team's assists charts and has played more key passes than any team-mate.
The 25-year-old suffered a dip in form in the New Year but Mertesacker puts that down to acclimatisation. Like Ozil, the Germany centre back had an up-and-down first year before going from strength to strength.
I think he has adapted well but there is more to come from him. I think the second season will be much better for him because he's a fantastic player
"It's very important to understand the differences between the leagues," Mertesacker told Arsenal Player ahead of Ozil's return to action at the weekend.
"Mesut came from La Liga and it's quite difficult to play there. I think he has adapted well but there is more to come from him. I think the second season will be much better for him because he's a fantastic player.
"He has shown some great skills but he needs to be more consistent, which makes a difference at the end. Sometimes it's good to get criticism with the negative points… if you are intelligent enough, and he is an intelligent footballer. I think he will sort that problem out.
"It's similar to myself when I got my injury in the second part of my [first] season, and after I came back even stronger because then I realised what is at stake.
"I think for Mesut it was good to get a little rest to be ready for the last few games for us, then the World Cup and then another season. I think with a pre-season ahead of him, there's more to come from him."Copyright 2017 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source