The midfielder arrived in the summer from Everton for a mega fee and has become a mainstay in the team.
While Onana knows he can still improve in many areas, he credits manager Unai Emery with already making him a more complete player.
Birmingham Live quote Onana as saying: “Unai has added a lot to my game.
“I think I am a completely different player if you compare it to last season at Everton. He has added bits to my game which I didn’t have before.
“I am really, really grateful and thankful for that. My start has been good, but it could have been better.
“I can still improve on different aspects and parts of my game. I am learning day by day.
“The manager is one of the best in the business. I am looking forward to continue working with him on a daily basis.”