The Belgian moved to Goodison Park on transfer deadline day on a season-long loan deal, having enjoyed a successful spell at West Bromwich Albion last term.
The Toffees have only managed two goals in their opening three Premier League matches so far this campaign, but Martinez is hoping that Lukaku can find the side's missing spark.
"I think it's fair to say that our opening three performances in the league have been really, really good, but all they have been lacking is that goal – the ball hitting the back of the net," Martinez told reporters.
"The fans realise that and when you see a player arrive who is capable of doing that it excites you. He could be that little piece which completes the puzzle.
Lukaku scored 17 goals at Albion last year.