The young German provided the assist for Santi Cazorla's opener and also went close himself in the first half with a fierce left-footed effort that flew just over.
Arteta praised the 18-year-old's technical qualities and believes he deserved his chance to impress.
Technically, he is very good but he's got something about him as wellMikel Arteta
"I think he's got a lot of quality," Arteta said. "He's got something not many players have in this team, which is pace and skill to go and beat people.
"That's why the manager played him - three up front is something that helps us be more incisive.
"We want to go behind [the opponents] and get into one versus one situations. Gnabry is very good like that and I'm very pleased for him because I think he did really well.
"He's like a little boxer, he's a little fighter. He's good. He's got a lot of character as well, the lad doesn't get intimidated either because it's a derby.
"His character is great. You see it in training. Technically, he is very good but he's got something about him as well. He doesn't mind when he gets kicked, he gets up and goes for the next ball. He's quite brave."Copyright 2016 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source