The Serbian became the Portuguese’s third – and final? – signing of the transfer window earlier this month, arriving for a fee of £40m from Chelsea.
And he has wasted no time settling in, producing a resolute, commanding display at the base of midfield on his competitive debut against Real Madrid.
Speaking to the club’s official website, Mourinho revealed that Matic was a player he wanted to see in a red shirt from day one.
“When I joined Manchester United last year, I thought immediately that we needed a kind of Matic,” he said. “There are not many – there are just a couple – but I thought that.
“But I was not thinking of it because I always thought I never like to go to players that I think are an impossible mission, and I felt there was no chance.
“Then this season, when I got the call that Matic wants to play for me and for Manchester United, and he can make it happen, I thought he’s the perfect player for me. Not just for his qualities but also for my relationship with him, the way I know him, the way he knows me.”
“I think he’s one of these players where there are no question marks in front. He doesn’t need time to adapt, he’s not a young guy who came from another country, he’s not somebody that needs to learn the Premier League.
“He’s a player of, I think, now 29 last week – 29 years old, with five years or so in the Premier League, lots of experience. He’s one of these players that gives me what I like in players, which is consistency.
“Matic plays normally here [gestures to a height with hand], and sometimes a little bit here [adjusts hand slightly] and sometimes a little bit there [lowers hand slightly] but Matic is Matic.
“And that’s something I really like in players – consistency. It’s the way I trust the player is going to perform, so I think it was a fantastic signing for us.”
It was often said that Roy Keane was Sir Alex Ferguson on the pitch; and Matic, whether at Chelsea or United, clearly serves as the Portuguese’s chief inflictor of his ruthless vision.
Above anything, his figure connotes domination – a kind of steady, unerring push towards inevitable victory. Not pretty, not likeable, but always effective. He understands the score under Mourinho better than any player in this current side.
And in this sense he is much more than a midfield reinforcement. In fact, his introduction spells the moment where this United team, following a year of moving in the right direction, starts to be a Mourinho team.