Mourinho, whose Real Madrid side open their Champions League campaign against City on Tuesday night, compared the investment made by Sheikh Mansour bin Zayed al-Nahyan since he bought the club in 2008 to that of Roman Abramovich at the Portuguese's old club Chelsea.
He said: "I don't think it is very different to Chelsea. Since Roman bought the club, (Claudio) Ranieri was the first coach, then I came and we won the first league, some cups and some more titles. Carlo (Ancelotti) then came and they continued to win and finally they won the Champions League."
He added: "With City it started off with Mark Hughes, they started spending money and buying good players. Then Roberto (Mancini) came and he has done a very good job. He has created a great squad, the first cup then the first title arrived.
"I don't know if it is this season or next season with Roberto, or with another person in the future, but normally in the direction the club is going, sooner or later they will win the big cup."
Real have started their own domestic campaign poorly, winning just once in their first four league matches, but Mourinho insists he will not make wholesale changes despite questioning some of his players' commitment after Saturday's 1-0 defeat to Sevilla.
"The line-up will not be very different, nor will I try to show any player that they are not in the best condition," he said. "It will be the best that I consider to play against opposition full of players of the highest level.
"I don't believe I have created doubts. The principal person responsible is me. When my teams win, we win together, and when we lose, I am the one responsible.
"Football is about today and tomorrow, not yesterday. Yesterday is history. I haven't been able to keep my players motivated and concentrated at the top level and that is my fault."