Speaking as a pundit on ITV's.
"I think every step in his career he got it, he grabbed it with both hands", said Mourinho.
"Maybe two years ago if Paul Pogba was part of the Man United team and he got injured, you'd go, 'Oh no, who is going to replace him?', because the squad wasn't really that strong".
In-form Lukaku will play his 12th match of the season for club and country when he faces pointless and goalless Crystal Palace at Old Trafford today - and that figure will rise to 14 by the time he returns from duty with Belgium in the forthcoming worldwide break.
Now Lukaku's fine run of form has seen himself earn a place in the Old Trafford history books.
"I don't want to speak about this progress".
"That's the only thing that concerns me and makes me think".
"For all top United strikers over the years, [the test] has been scoring the big goals in the big games".
"And we have to play tomorrow so mentality is very important".
Mourinho added: "This week is a good example because it's a week where next week is global football so why can't you play Sunday?"
"We are humble, we know that the great teams of the Premier League we didn't play them yet, so we are calm, we follow our work".
His behaviour on the touchline cut an uncanny resemblance to that of Pep Guardiola who was also unhappy, despite leading, with his Manchester City side's first-half showing against the same opponents.