At Everton, there would always be those big games where Lukaku would be left on his own up front to basically hold the ball, dribble from half way line and score while rest of his team sat behind the ball. I don't think he understands how to play that role. He's always worked hard when his team actually has the ball. He was an arrogant prick at times though. But that was mostly off the field when he would openly admit that he wants to play for a bigger club.
Lukaku is not a Zlatan type striker in the sense that he won't come short and try to let other players run beyond him and be a play maker. He needs a number 10 near him. In games where we leave him up on his own, he will still look average. But luckily we won't have too many games this season where we sit back behind the ball.