Mertesacker expects him to showcase his more familiar attacking spark than seen at the Euros with Germany when he arrives at Emirates Stadium.
"Defensively it was a great game from Lukas," he told Arsenal.com.
"He had to cover for Philippe Lahm, with Arjen Robben on his flank, and he did it very well. Especially in the first half, he covered him all the time and it was two against one on Robben.
"I think that was more important than his attacking qualities today. But every Arsenal fan will soon see what he can do offensively."