Arteta handed Max Dowman a Champions League debut on Wednesday night, at 15 he became the youngest player to feature in the competition.
The manager said afterwards: "What he's done on the pitch is that he comes in, the first ball he takes, he takes people on, he starts to dribble, and gets a foul. That's personality, that's courage and that you cannot teach that. You have it or you don't, and it doesn't matter what his passport says.
"You throw him in this context and he's ready to adapt and have a good performance. So, I'm really happy with that."
On two-goal Mikel Merino, Arteta said: "It's a joy to have him, I always say the same thing. It's his versatility on the pitch, the things that he can do, it's his mindset, it's his leadership, it's the way he is as a person. Today we are missing a lot of attacking players and we have to find different solutions, he comes in the Champions League and scores two goals.
"You have to invent options, you can always have options if you invent them. But obviously, Mikel hasn't played there before in his career, but we had a good experience of last season, and the way he reacted and performed in that position. And obviously, we believe that today, the way it is, there was a good chance for him to perform.
"My view was always that he had really good timing and the capacity to finish in the box, especially one-touch. And then talking to him and making sure that he plays closer to the box, and he identifies the opportunities, the timing, the way he needs to attack the spaces in relation to how they defend the box, which today was a bit different as well, the way they set up. And then it's obviously his quality. his willingness to learn and practise every day."
Arteta also had a word for Piero Hincapie and his performance at the back.
He said, "Very happy, he can play in those two positions, as a centre-back or full-back. Today, the way we had to set up and the situation that we have to imagine with the ball. I think he was really good, really strong, really efficient and really good, because now he's got some minutes in the last week with two games and the last minutes against Burnley. So, we're getting him up to speed. "