The Gunners overcame Bournemouth 2-1 at Vitality Stadium on Monday night, with their pair of first-half strikes. The victory ended a three-game winless run for Arsenal.
“In the first half I think we were really, really good,” Arteta said.
“I think they executed everything that we planned in a really good way. They have courage to play, they have courage to make big decisions.
“They’re important in this side. They’re not the icing on the cake.
“They’re probably the core of that team at the moment and to play with that accountability and decision, I really like it.”
Saka, 18, continues to impress for the Gunners even playing at left-back, with his pass setting up Nketiah’s goal.
“It’s the situation now because we don’t have any left backs at the moment,” Arteta said.
“What I like is that he’s put his head down, it’s not his favourite position to play, but we try to adapt him with his qualities to play him as much as possible in the position that he likes.
“But then he is very willing to learn all the defensive principles that we are asking him to do and his attitude is really good.”
The Spanish boss also addressed talk about captain Pierre-Emerick Aubameyang potentially moving to FC Barcelona during the January transfer window.
“I want Auba here 100 per cent,” Arteta said.
“I’m so happy with him and I can’t wait to have him available again after suspension.”
Arteta also said he isn’t expecting “good news” on defender Shkodran Mustafi after being stretchered off in the second half with injury.
“They’re going to assess him between today and tomorrow but when a player has to come off, normally with a central defender - hopefully I am wrong but - normally it’s not good news,” Arteta said.