don't know about that - brazilians, attacking players at least, usually don't adapt too well in the EPL, so Lucas going to ManU is a bit of a risky move for his career, I think. The same goes for Oscar, btw.
my gripe with Lucas is that while being very talented on the ball (hence why he is so popular with fans) he is a very limited player tactically, in terms of footballing intelligence; not a team player but too big an individualist, which makes him one-dimensional/predictable and easy to stop once you figure him out - the Brazilian Krasic, so to speak.
I expect him to have some success at first but once the EPL defenses get used to his trick (get the ball and run around with it till he loses it), he would be as big a secret to them as an open book, me thinks.