"I am really pleased Theo got the chance to play in the last two games," said Rooney. "He must still be on a high after that hat-trick against Croatia.
"It was so good to see him respond the way he did.
"I don't really have any advice for him. He just has to keep enjoying it and playing well because he will be a great asset for us.
"He brings something different compared to what we have had before."