The Gunners booked their place in the knockout stages of the competition, with further goals from Reiss Nelson and Folarin Balogun completing a comprehensive victory over the Norwegians.
Pepe was a bright spark in the Arsenal side during the game, and his performance and attitude was in sharp contrast to the one he put up against Leeds United in the Premier League last Sunday, when he was sent off for a headbutt on Ezgjan Alioski.
That incident incurred the wrath of his manager, who accused Pepe of letting his teammates down in the stalemate at Elland Road, but Arteta sung a different tune on Thursday after the former Lille man scored his third goal in four Europa League games this season.
"I am really pleased," Arteta said of Pepe. "Obviously after the disappointment, something negative, you want to see a reaction and to stand out really quickly.
"I could see from the first minute, from his body language, that he was ready to act. I think he had a great performance.
"He scored a goal, he could have scored another one or two. He created some great moments in the game and worked really hard for the team. I really liked it. I am really pleased with that.
"We all know where his level is and all the time the question is how often he can get to that level – and how he contributes to other aspects of the game.
"That should be the level that he needs to hit and from there he needs to keep improving, because he is capable of doing it and you can see that every time he gets in those positions, in the final third, he is a real threat and a really difficult player to control.
"He can come with his feet, he can go inside, outside, he can shoot and create crosses. He can go in behind you as well. That's what we expect from him."
Pepe will start the first of a three-game domestic ban when Arsenal face Wolverhampton Wanderers on Sunday. He will also miss games against Tottenham Hotspur and Burnley.
