Calafiori forced home a header inside the opening 15 minutes at Old Trafford for the only goal of the game.
Arteta said of the Italian afterwards: "He has the capacity to change the energy. He comes in this room and he changes the energy in the room, he changes the energy in the team. He has an aura, he has a presence that is special.
"And then he's a player that is very unpredictable for the opponent because he can occupy very different spaces, he can do things in and around your box, in the middle, in the opposition box, that is very difficult to predict. So, very happy with him."
On winning without playing well, Arteta also said: "Well, that gives you certainly momentum and confidence - two very important things. Because you know that when you know your standards in certain aspects, which today we weren't, being fair, we can still come away and find a way to win the game.
"And the team has to find that resilience throughout the season for ten months in different contexts to be able to do that. Of course, we have to improve a lot of things and that will happen very soon. But in terms of managing to get that into a very positive result, that's a great way to do it."