The City manager says last season's title came too soon.
"It's difficult to win a championship here," said Mancini. "We won last year but we won very quickly. Usually when you manage a team that hasn't won for 40 years, I think that you need four, five or six years to win a Premier League.
"We won the championship after two years and it's clear it's more difficult the year after but we had the chance."