The German international has been solid this season for the Gunners after enduring a tough first campaign in the Premier League.
"Maybe he is less elegant and the visual impression is less pleasing but he is efficient and intelligent," Wenger told reporters.
"He combines well with both [Thomas] Vermaelen and Laurent Koscielny. They are good partnerships. He is a bit better at positional play.
"I have three good centre-backs. I can't be wrong when I make a decision because all three deserve to play."
Mertesacker has played 39 games this season for Arsenal in all competitions.