Having masterminded Manchester City's first English title for more than 40 years last season, after ending their long trophy drought by winning the FA Cup 12 months earlier, the Italian might have anticipated some smooth waters this season.
They are turning increasingly choppy, however, following United's last-gasp 3-2 victory in the derby, after which Mancini could not resist pointing the finger at some of his players.
He did not hold back when discussing his reasons for hauling Balotelli off just after halftime and mocked Samir Nasri when suggesting that there were only "two and a half players" in the wall when Robin van Persie fired a stoppage-time winner.
City's first league defeat of the season, an unlucky one at that, hardly represents a crisis and Mancini was quick to predict that his side will win the league and FA Cup double this season, but the coming months will be a test for Mancini.
Out of the League Cup and the Champions League before Christmas after finishing bottom of their group, maintaining harmony in a squad bulging with internationals, many of whom kick their heels on the bench, will not be easy.
League games will come thick and fast over the holiday period and City need a calming hand on the tiller if Mancini's bold claim does not return to haunt him.
Three of City's next four matches are away from home, and while trips to Newcastle United, Sunderland and Norwich City, should hold no fears for Mancini's team they know they can ill-afford any slip-ups.
Midfielder Yaya Toure, whose goal sparked City's comeback from 2-0 down against United on Sunday, said the team had to buckle down and work hard to repair the damage done by two draws and a defeat in their last four league games.
"We have to forget what we have done in the past. This year will be tough, but we have a fantastic squad and we have the confidence to keep going until the final day," he told City's website on Monday.
"Last year was fantastic, but we have to realise that sometimes you go through tough periods - we can turn this around. When the chips are down, that's when the tough really get going and we will show why we are champions.
"Disappointing though this defeat is, it only makes us more determined to win the title. We have to be strong mentally and strong in every other way as well, but our championship challenge is not finished."
Those comments will be music to the ears of Mancini.
While his vast spending power is the envy of virtually every manager in the world, Mancini's demeanour during matches often resembles that of a scientist struggling to keep the cork on a test tube full of highly volatile chemicals.
With so many egos colliding in the soap opera world of the Premier League, it only takes a couple of setbacks to start tongues wagging and Mancini's man management skills will be tested to the full over the coming months.
"Nothing has changed for us - we need to work hard but there is a long way to go. We have proved before we can win the title from situations like this," Mancini said.
"We have the players and the spirit to recover and I believe we will still win the Premier League and FA Cup doubl
