Arsenal will host north London rivals Tottenham in the third game of the new Premier League season, but Mertesacker says there is more than just the derby to focus on.
"We are looking forward to the Tottenham game but first we have to think about the Champions League qualification matches," he told arsenal.com.
"They are vital because our first target of the season is to get into the Champions League group stage. We have to prepare well because I think all the supporters are desperate for us to be in the Champions League again.
"So that's the first target, and we are looking at the first league fixtures, especially the derby game, as well of course."