United striker Wayne Rooney will be the subject of a third bid from Chelsea after the bank holiday encounter at Old Trafford, when Belgium forward Lukaku aims to build on his 17 goals on loan for West Brom last term.
"I'm getting closer to where I need to be and hopefully also closer to the starting line-up, my main ambition," the 20-year-old former Anderlecht striker told Chelsea TV.
"If I keep working hard, like I'm doing now, showing the talent that I have hopefully I get to start in the next game. Compared to the first year, when I arrived here it was all about learning and taking a bit off all the players, now it's about starting games."
The physically imposing Lukaku offers a different attacking threat for Chelsea than the playmaking trio deployed directly behind the lone striker - any three from Eden Hazard, Juan Mata, Oscar, Victor Moses, Kevin de Bruyne and Andre Schurrle.
Lukaku can hold the ball up, link the play, and occupy the attentions of a number of defenders, rather than drop deep to add to the playmaking congestion.
"When you have three players like that behind you, if you come towards the ball it makes one player too much," Lukaku said.
"You need that one guy to go in there, that's a good thing, that's what I like. When they go to the ball I'm around to block a defender, flick the balls on or run on at the back of defence."
Lukaku is often likened to former Chelsea striker Didier Drogba, who he used to sit next to in the dressing room on his arrival from Belgium. Mourinho has been wary of the Drogba comparison and Lukaku is too.