Lukaku has come in for criticism from Belgian pundits for moving too soon to Chelsea.
"From what I've seen in (Belgium) training, he's still enthusiastic and confident," said Kompany. "If I compare him with last year he has also become better. I know there is alot of talk about him not playing often for Chelsea, but he has made a lot of progress.
"I play in the Premier League every week against top strikers and I dare say Romelu, even now, is inferior to them."