"I've been very impressed with him. When we bought him we knew he had ability but we thought he was going to be one for the future," said Molby.
"We're very well off in centre midfield with Gerrard, Alonso, Mascherano and Sissoko but he's obviously made an impression on the training ground and earned his chance in the first team.
"It's difficult to say what type of player he'll go on to be but it seems he has a bit of everything. He's very calm on the ball, he is a good passer and he can also get forward and make chances.
"The good thing from my point of view is that he is one of a number of young players who are already doing well. Rafa has players like Reina, Arbeloa, Babel, Agger and Torres - all of whom are young but all of whom are already good enough. Lucas falls into that category as well."
