Substitute Kai Havertz rubber-stamped Arsenal’s fourth win from six games in this year’s competition in the 88th minute.
“In the first half we should have put the game to bed but we didn’t,” Arteta said.
“In the Champions League you will have difficult moments and we suffered.
“Then with the second goal the game was in control.”
With defensive injuries forcing his hand, Arteta gave a first Champions League start to 18-year-old Myles Lewis-Skelly and the left-back played a key role in Saka’s opener.
Shrugging off a challenge, he showed great vision to pierce Monaco’s defensive line with a pinpoint pass to Jesus who slid the ball across the area for Saka to convert.
“A really proud moment,” Arteta said of Lewis-Skelly.
“He is one of our own and a joy to watch. It’s great we can trust him to play in this environment.”