The Portuguese tactician claims that expectations should be high for the club because of their summer spending.
"I know the players they've bought," said Mourinho. "Navas and Negredo are world champions, European champions, both 27. Jovetic, for more than two years, has been one of the best in Italian football, a 23-year-old who has five years at Fiorentina, playing in Serie A at the highest level.
"Fernandinho is more than that because he has more experience, a national team player, big experience too. I think they are players without surprises who are more than ready for the Premier League.
"If you see their age, their maturity, they are in the perfect moment of their career to go to England, and there will be no need for adaptation, no need of work to learn the project. They are players at the top of their careers, experienced but still young, so I think they've bought very, very well."