Oxlade-Chamberlain scored twice as Arsenal beat Reading 2-0 in the EFL Cup on Tuesday night and Arsene Wenger feels that the winger has now come of age.
"He is not a young player any more," Wenger said about the England international after his brace in the cup.
"He is now 23 and at 23 you become a football player who is the finished article. Before 23, you learn your job.
"At 23, you become more consistent, you know what's expected of you, you know how to deal with the pressure, with the situation, with the competition inside the squad.
"But he was so talented, so young. In the national team, so young. People forget that he was still a young player.
"I think he has added some belief to his finishing. Now we have hope that whenever he has the ball, something can happen.
"He's powerful but he also finishes well and he's added that to his game. That's certainly linked with confidence, hard work in training, and he looks to be following Theo Walcott in that way".
However, despite an upturn in form this season, the 23-year-old is still not a regular in the Arsenal starting XI, although Wenger feels that the former Southampton man is not far from becoming a regular starter.
"He's not a long way away from the starting XI because he played against Ludogorets, he played tonight which was expected, but Ludogorets was a very important game. He came on against Middlesbrough on Saturday and I feel that he is regularly involved," he added.