The Italian has also been forced to dismiss claims that his job is under threat due to an underwhelming season, which has seen his side fail to make a mark in Europe, fiinishing bottom of their Champions League group.
Yet Mancini has insisted that his long-term project could see the club lift the Champions League in as little as five years' time.
"I don't think I can stay here 10 years," Mancini told reporters. "It's impossible for me to do that. But I think that in four or five years, to try to win the Premier League and Champions League is possible.
"Nine months ago we won the Premier League and six months ago we won the Community Shield.
"Now we have another two chances. Maybe the Premier League will be difficult, but we have the FA Cup.
"Hopefully, if we can take second place, that would not be a bad season, like United last year."Mancini added that he thinks it would be a mistake if he was to be sacked, claiming that a club needs stability to be taken to the next level and challenge for European trophies.
"It's impossible that in two years we can be like United, who built their teams over 20 to 25 years. That is history. To build a team like United or Barcelona you need five, six, seven or eight years.
"When I signed my new contract last summer, it was for five years because I wanted to build a strong team and continue at this club.
"I think for every club to have stability is important. If you change the manager every one or two years, it's difficult.
"But if I didn't win for two or three years, I would say to the club, 'I don't want to stay', because after two or three years of not winning, I would leave.
"I couldn't continue to stay here. It would be impossible for my mind to think like this. But I think that what we did in the last two years is important for the club.
"After, of course, in football anything can happen. Some teams change their manager at the end of the season. I know this."