Zola told whufc.com: "It is down to him and everybody knew he was good at keeping the ball and playing for the team but now he is focused on scoring goals, which was the thing that was missing.
"We are trying to improve him, helping him in training sessions and make him better in this way. Now he is scoring goals and is getting them. It is just about focus and his focus is right on target now. It is a great partnership. They are playing with each other a lot and helping each other but also the rest of the team. They are more than strikers and they are very impressive."