It has been suggested that the 48-year-old Italian could be sacked if his side are knocked out of the FA Cup by Championship side Leeds on Sunday.
The odds are stacked against City retaining the Premier League title they won in dramatic fashion last May, with Manchester United currently 12 points clear of Mancini's men with 12 games remaining.
Speaking at a press conference ahead of Sunday's FA Cup tie at the Etihad Stadium, Mancini said: "We started our project three years ago. In three years we are always on the top - we fight for the title, we have won three trophies, we have the chance to win more this year.
"All the people who talk about this don't understand football.
"If Manchester City should sack me, the other 20 teams in the Premier League should be without a manager."
Mancini, who succeeded Mark Hughes in December 2009, ended City's 35-year trophy drought by guiding them to FA Cup success in 2011 and followed that a year later by overseeing the club's first title win in 44 years.
Last weekend's 3-1 loss at struggling Southampton has brought renewed speculation over Mancini's position with former City player Danny Mills suggesting the Italian's position is perilous.
When told he had been criticised by "former City players", Mancini responded by saying they were "probably the players that won a lot of trophies in the history".
Mills said: "Mancini is under pressure. It looks like they have blown their chances of retaining the title. You wonder what would happen if they went out of the FA Cup against Leeds. I think Roberto Mancini goes."
Mancini added that he has not yet accepted defeat in the quest to catch Manchester United at the top of the Premier League, despite the sizeable gap between the sides.
"I don't think like this, I have a different mentality," said Mancini. "I always think we can do everything. We have 12 games, we need to do our best and not look at the table."