Vieira admits Benteke is now nearing his best.
He said, "[What have you done to change his game?] "Nothing really. I think again it's all credit to Christian. He showed he wants to be part of this football club. The fact we brought in [Odsonne] Edouard as well, bringing challenges for those players to challenge themselves. Christian is up for the fight to show everybody he wants to be part of what the football club is trying to do.
"He put his head down, is working really hard and is close to his best.
"He's playing with confidence, belief and he can score goals. When you score goals you believe even more in yourself. When the team are playing well, with confidence, it allows players to express themselves. We have to maintain that."