Aged just 15 years and 181 days old, the midfielder was born in 2007 - before the Emirates Stadium was finished.
Arteta praised Nwaneri for his contribution in first-team training ahead of the game for a debut in Martin Odegaard’s absence.
“It was a pure gut feeling. I met the boy, I really liked what I saw,” he told reporters.
“I had information from Per and Edu, he trained with us a couple of times. He had to come with us because of Martin’s injury and I had that feeling yesterday that if the opportunity could come, I would do it. He deserves it.”
William Saliba, Gabriel Jesus and Fabio Vieira all netted in the cruise past Brentord.
“[Saliba] has been superb, he hasn’t trained for ten days,” said Arteta.
“He had some discomfort, he only had one training session and he comes in and competes the way he does. And the ugly part of the game as well, which people don’t recognise too much. He deserves some credit.”