The Portuguese coach believes that there are still six teams in the title race, but has admitted Manchester United and Tottenham Hotspur cannot afford to lose any more ground on the early-season pacesetters.
United and Spurs are currently nine and 10 points respectively behind leaders Arsenal, while City are six adrift, and Mourinho feels that Manuel Pellegrini's side have the most pressure on them to lift the trophy.
"I don't think we can speak about favourites but we can say that one team is top of the league and some are a little bit far [behind] but I keep thinking that all the six teams are title contenders," he told reporters.
"I keep saying the team with more responsibilities to win it, because their squad is quite unique, is Manchester City.
"Spurs and United know if teams reduce [their points gap] from 10 to seven, or to six, they are again into the race. But I think they also know if the move is from 10 to 13, or nine to 12, it becomes hard."
City are 13/8 favourites with Sky Bet to win the Premier League, with Arsenal available at 5/2, Chelsea 3/1, Manchester United 10/1, Liverpool 12/1 and Spurs 66/1 with the same bookmakers.