Per the Daily Mail's Chris Wheeler, Matic—who won the Premier League title with Mourinho at Chelsea in 2015 before reuniting with him at Old Trafford last summer—discussed the expectations the Special One places on his players:
"It is very difficult to work with him because he always wants more and more. Even if you win the league he wants to win again next season. He is like this and the players need to be ready for that.
"He is special because he wants to win always. You can see when we lose a game he cannot accept that. Probably that's why he won more than 20 trophies in his life.
"Because at this high level, at Manchester United and where I used to play at Chelsea, the players need to be ready for that because the pressure is big."
Despite watching his side beat Brighton & Hove Albion 2-0 on Saturday to reach the semi-finals of the FA Cup, responding to their UEFA Champions League last-16 exit at the hands of Sevilla, Mourinho was unhappy with many of his players.
Per BT Sport Football, he singled out Matic for praise after he contributed a goal and an assist in the game, but he was otherwise critical of what he saw:
Samuel Luckhurst of the Manchester Evening News felt the manager was right to speak out:
Samuel Luckhurst @samuelluckhurst
High time Mourinho dug out players. Matteo Darmian a case in point today on his wife's Instagram. Injured or not, he is comfortable and carefree at United, and lacks the basic professionalism required at #mufc. Some others need to be fighting for their careers at the club.
In light of Mourinho's strong comments, Bleacher Report's Dean Jones was hoping to hear from the dressing room:
However, Matic enjoys being pushed to the limit by his coach.
"I like it when the manager always wants better and better, so you have to improve always," he added. "I like this kind of work, this kind of relationship. I'm happy."
It's likely a number of his team-mates would disagree. Mourinho hauled off Luke Shaw at half-time despite the 22-year-old producing a fairly good performance, and the Portuguese criticised the left-back after the match.
One of Mourinho's tasks upon taking over at Old Trafford was to instil the kind of winning mentality United displayed under Sir Alex Ferguson that was lost under successors David Moyes and Louis van Gaal.
As such, he should be holding the players to a high standard, but he has perhaps gone too far in his criticism of the team—while Matic may thrive under such conditions, he risks alienating others.
Football journalist Tom McDermott is concerned about the manager's approach and likened it to other difficult moments in Mourinho's career:
United's players are capable of performing at a much higher level than the standard they have shown throughout the season, but Mourinho should also bear plenty of responsibility for failing to get the best out of them, both tactically and through his man management.
As for Matic, it's clear why Mourinho wanted to bring him to United, both for his performances and as a supportive voice in the dressing room.