The Portuguese boss cited the vast sums of money the defeated FA Cup finalists have spent on a group of experienced players this summer, while the Blues have signed the 22-year-old Andre Schurrle and 20-year-old Marco van Ginkel.
Mourinho believes that his young side are far from the finished article and in need of learning experiences, while the pressure is firmly on City to pay back their vast expenditure with a serious title challenge.
"Of course," the Blues boss told reporters when asked if more should be expected of City than Chelsea. "Young players are not at the best they will be. They need to learn, they need time to get to the top.
|9/4||Chelsea are 9/4 with Coral to win the Premier League
"[Stevan] Jovetic, for more than two years, is one of the best in Italian football. He has five years of Fiorentina, playing in Serie A at the highest level. Fernandinho has more experience, a national team player.
"I think they are players without surprises. They are more than ready. If you see their age, their maturity, they are in the perfect moment of their career to go to England, 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. They bought very, very well. That doesn't surprise me because they have the money to buy but also the knowledge. They have people in the club that know a lot about football."
Given the inexperience of the Chelsea squad, Mourinho believes that a title win this season could be the best of his highly-successful career, while continuing to ramp up the pressure on Pellegrini to succeed.
"It's different," continued the Portuguese. "It can be better because I always say that the best trophy you have is the last one. If we win something important with this group, it will be the best for many reasons.
"In my first time you [the media] were always putting pressure on me saying: 'You buy this, you spend that, you buy the title.'
"So I hope now it is on the other side. It's always difficult to win. You can have the best players but you have other kinds of problems."