Mertesacker provides a commanding presence at 6ft 4in, and Vermaelen maintains there should be no issue with whatever selection the manager makes this weekend.
"I only trained for a short time with Per before that [Marseilles] game because I had been injured since he came to Arsenal," he said.
"For me it was a bit strange because I played alongside him for the first time straight away in a Champions League game.
"But we know each other's qualities because I have seen him in games and you know where the other centre-back is going to be.
"I don't think it is a big problem."