The Ivorian scored a cracking goal to break the deadlock, with the Gunners eventually winning 3-0.
The match came just a few days after Pepe was sent off for a headbutt against Leeds United.
Asked about Pepe after the game, Arteta said: "We all know where his level is.
"All the time the question is how often can he get to that level and contribute to other aspects of the game. Today is the example."