Lukaku scored today in victory over Real Salt Lake.
Mourinho revealed: "I think it's just nice for him but not important for me. When he came [over to the touchline] for the 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's not important.'
"He holds the ball so well, he plays one touch, two touches so well. He sees, he moves, he gets behind people, he attacks crosses, he works with the team and when we lose the ball he presses well. I like everything he does.
"For me, it's 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 is just a detail, not important."