Fosu-Mensah, 18, enjoyed a breakthrough campaign during the 2015/16 season under Louis van Gaal, making 10 appearances in all competitions.
The Dutchman insisted that he is looking forward to next term under Mourinho, who was appointed as Louis van Gaal’s successor at Old Trafford last week.
“I’ve never heard a player speak badly about Mourinho,” Fosu-Mensah said.
“I’m curious — I want to develop into a top player for Manchester United under him. That’s the next step in my plan. You’re 18 and you’ve had van Gaal and Mourinho as your managers. Really, it’s unbelievable.”
Fosu-Mensah has enjoyed a remarkable start to life at United. He put in top performances against the likes of West Ham United and Tottenham Hotspur and his pace, power and technical ability despite his tender age means there are real hopes that he will develop into a quality player.
Of course, there is a lot of work to be done under Mourinho, who has a reputation as a manager who neglects young players, but the initial signs have been good.
Along with the likes of Cameron Borthwick-Jackson and Marcus Rashford, United have a talented crop of youngsters coming through. Mourinho would be wise to include them in the squad next season in order to keep the fans on his side.