Speaking at his first news conference since replacing Mark Hughes at the world's richest football club, the 45-year-old Italian wasted no time setting his targets.
"Next season we want to win the Premier League," said Mancini who revived Inter Milan's fortunes by claiming three successive Serie A titles from 2006-08.
"My target this season is to arrive in the top four. I think it's possible. I hope to stay here for many, many years and win many trophies because I think City has great supporters."
Chief executive Garry Cook said the club first discussed a change of manager during a run of seven consecutive league draws which stalled City's early-season momentum.
"The decision to seriously look at managerial options was taken three weeks ago following the Hull City game," said Cook. "I would like to stress Roberto was only offered the job after the Spurs game (a 3-0 defeat last Wednesday)."
Mancini said he had sympathy for the man he replaced but relished the prospect of trying to lead City out of the shadows of their more illustrious city rivals United.
GOOD CLUB
"I am proud to get the job because City is a good club with good players," he said. "Manchester is similar to Milan in its football passion.
"In Milan there are two big teams there fighting for supremacy and silverware and here it is the same. I like the challenge of that."
Mancini's title with Inter in 2006 was the club's first Scudetto since 1989 and ended more than a decade of playing second fiddle to AC Milan.
"I'm sorry for Mark but when we start the job this situation is always possible," said Mancini. "I think I can do a good job because we have good players."
"We have five or six top players in attack. There are many options," he said. "Robinho can make history for Man City like I wrote the history at Sampdoria. For me this is important."
