Jose Mourinho's appetite for success means "sometimes it isn't easy to work with" the Manchester United manager, but Nemanja Matic has never played under a better boss.
The pair were Premier League winners together at Chelsea little more than two years ago, and now they are looking for more success after being reunited at Old Trafford this summer.
The initial £35million outlay for Matic already looks shrewd business, with his fine start to the season.
The Serbian shone at the club he once called home, while Mourinho also has links to the Lisbon giants having had his first break in management with them.
The spell ended abruptly but the United boss has since enjoyed an upward trajectory that Matic is sure will continue at Old Trafford, even if the players are in for a tough time now and again.
"Mourinho is a brand, and the best coach I've ever worked with," the defensive midfielder said.
"Sometimes it isn't easy to work with him, because he always demands more.
"Even when you play the best match in your career, he considers that you can play better in the next match.
"I co-operated excellently with him at Chelsea, and the fact that Mourinho is the coach at Manchester was the decisive factor in my choosing my new environment.
"Privately he's completely different from the way he is perceived by the general public.
"This is a man who possesses all human virtues. He's not at all cold or conceited, as he is presented in the media.
"He has created an excellent group of players with huge potential, and everything is there for us to achieve good results.
"I don't want to talk about the goals of the club, but when I mention Manchester United I think the ambitions are clear to everyone.
"We will do our best to achieve the results that previous generations had."
It was a happy return to Benfica for Manchester United midfielder Nemanja Matic who spent two-and-a-half years with the Portuguese side. pic.twitter.com/mesQacXZma— RTÉ Soccer (@RTEsoccer) October 18, 2017