Saka scored in the 3-1 win on Saturday.
Arteta said of Saka: "That’s the maturity and the steps that players have to do. He’s been long enough in the team now, he’s earned the right to have that role, he believes in that. He has the capacity to change games, to decide games, like many other players. If you want to be at the top, sometimes players have to create those moments and he's certainly done that today.
"It’s another step ahead in what he wants, especially when. Do it at home, do it away, do it in big games, do it in some other games, when the team needs it, not when it’s 3-0 - that’s what defines a top, top player."
On Gabriel Jesus and Sterling’s performances, he added: "I was really happy. We made the changes, we had to make them and everybody deserves to play. In the first half it could have been very different to the result we had at half-time. After that we decided to change because the energy had to be changed and we brought on three players that have the ability to do that and they really helped. I’m really pleased with everybody."