Nemanja Matic has admitted it is not easy to work with Jose Mourinho at times, but said he has never worked with a better manager than the Manchester United boss.
Matic worked with Mourinho at Chelsea before reuniting with him at Old Trafford ahead of this season and has played a key role in United's bright start to the campaign.
The Red Devils are unbeaten in the Premier League and just two points behind Manchester City, while they have a perfect record in the Champions League group stage, with Matic playing every minute in both competitions so far.
While the Serbia international has a great deal of respect for the two-time Champions League winning manager, he says it can be difficult to live up to Mourinho's expectations.
"Mourinho is a brand, and the best coach I've ever worked with,” he said to Serbian magazine Elevate.
"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 cooperated excellently with him at Chelsea, and the fact that Mourinho is the coach at Manchester was the decisive factor in 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.
With United looking to get back to the top of English and European football, the club could not have put their faith in a better coach, the 29-year-old says.
"Mourinho 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.
"The fact that I'm playing for United is the pinnacle of my career and of everything I've achieved in football.
"I really like it in Manchester, and the family has got used to the city. I needed very little to make me happy in my new environment -- just to be together with my wife Aleksandra, my six-year-old son Filip and three-year-old daughter Tea.
"The children have a good school in Manchester, and I'm particularly glad that my son started football training. He has a place reserved in United's junior ranks."