The English youngster scored his first Premier League goal from West Bromwich Albion on Sunday.
"He's having an incredible season ever since he started to play in December," Arteta said after the 3-1 win over West Brom.
"But he's scoring his first Premier League goal. An incredible season for a No 10 of Arsenal means he needs to score 15 goals and give 10 assists.
"Then you are right up there with the top guys in Europe and in the league. He's got the ability to do it but he hasn't done it.
"We need to stay calm with him, give him the right support and step by step, I think he will be getting there."