Chelsea have kept four consecutive clean sheets away from home for the first time since December 2008.
Branislav Ivanovic has scored 21 Premier League or Champions League goals for Chelsea but this was his first with his left foot.
"The title race is between two horses and a little horse that needs milk and needs to learn how to jump," he said. "Maybe next season we can race."
Victory at Etihad Stadium meant Chelsea became the first team to do the double over Manchester City in the Premier League since Everton in 2010-11.
It was a deserved result for the visitors, who hit the woodwork three times in the match as they continually caught out Manuel Pellegrini's side on the counter-attack.
However, despite the impressive performance and result, Mourinho refuses to state publicly that his side are capable of beating Arsenal and City to the title this season.
"I don't agree we are title contenders," said the 51-year-old Portuguese. "We are a team in evolution but this is the kind of performance that helps a team grow up a little tactically and mentally. It was fantastic.
"We have beaten the best team, Manchester City, twice but they are the best team. I am not saying we are better than them but today we were the best team.
"We do better in these big games because we love it. We love the big games and when you love it maybe you feel an extra motivation."
Mourinho praises 'complete' Chelsea display
He added it was not Chelsea's "objective" to win the league, adding: "Our objective is to build the team.
"I want to start the next pre-season and say this season we are going to win the league. This season, I can't."
Mourinho also revealed the final words of inspiration to his team before they took to the field at Etihad Stadium came from masseur Billy McCulloch rather than the manager himself.
"He [Billy McCulloch] was screaming so much in his Scottish [accent] I didn't understand really." said Mourinho. "The players were clapping so I thought 'OK, that's good'. I'm serious."
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