The talent made his debut in a 2-1 loss in a Conference League playoff second leg against Servette.
As the Blues made it through over two legs, Maresca gave chances to some fringe players in midweek.
Asked about George’s debut, he told reporters: "I think he was good. The most important thing is he was not shy. He was (playing) with personality. He is a young player.
"We also had Josh Acheampong on the bench. Unfortunately Harrison (McMahon) was not on the bench but the idea is to slowly, slowly build something important with them and the academy players."
On Noni Madueke earning an England call-up, he added: "Very happy. He is doing very well. As I said after the Wolves game: now the most important thing for him is not to drop anything and continue to keep working hard.
“We are happy with him, Levi (Colwill), Cole (Palmer) and for the rest that they are going to be with international teams."