The £75m signing from Everton scored his first goal for the Red Devils during their 2-1 win over Real Salt Lake earlier this morning.
United's boss was quick to play down the importance of the strike, perhaps putting more importance on his first league goal.
But Mourinho is adamant there is more to the Belgian than just finding the back of the net.
The Portuguese is a fan of how Lukaku moves, attacks the ball and keeps possession high up the pitch.
Mourinho said: "Lukaku's first goal? I think it's just nice for him, but not important for me.
"When he came for water before he scored the goal, I told him: 'I love everything you do on the pitch'.
"'Don't be worried about scoring, or not scoring, because it is not important'.
"He holds the ball so well he plays one touch, two touches, so well.
"You see he moves, he gets behind people, he attacks crosses, he works for the team, [when he] looses the ball he presses well.
"I like everything he does. I like everything he does.
"For me it is easy to feel it because he was my player four years ago or something like that.
"His evolution was great.
"He's now a top striker and the goal was just a detail. Not important."
