A lot has changed since 23 October, 2011. From the high of the 6-1 Old Trafford victory, when the title seemed their's to lose, City now find themselves trailing bitter rivals Manchester United as the season turns into its most crucial period.
Regardless of how much Mancini has spent, credit must go to the manager for assembling several very expensive, very talented parts in a whole, complete team. However, cracks have recently begun to emerge in the Eithad's foundations, a difficult January preceding a costly away defeat to Swansea and elimination from the Europa League to Sporting.
City produced a fine second-half display against the Portuguese side but the damage was done in the 90 minutes in Portugal and the first 45 in Manchester. English sides have certainly showed the British bulldog spirit in recent weeks, Arsenal first coming close to overturning a 4-0 first leg deficit, then Chelsea's old guard sticking it to Napoli before a last-minute Joe Hart header brought City within inches of a four-goal comeback.
English teams in Europe this season seem to have picked up where they left off in the Premier League. Defending has gone out the window as the top clubs have contested uncharacteristically high-scoring games. In Europe, lack of defensive awareness and tactical organisation cost Arsenal four goals at the San Siro, almost cost Chelsea in Napoli while United and City's carelessness in the group stage saw them leave the competition earlier than expected.
Of all of the top English clubs, City have had the least problems defensively. Vincent Kompany has blossomed into the Premier League's best centre-half while Joleon Lescott has proven himself to be an able sidekick. It's no surprise that City's struggles have come when these two have been missing and the replacements haven't been good enough. Stefan Savic needs time but has done himself little favours with high-profile blunders while Kolo Toure is a shadow of the player he once was.
Defensive frailties meant that City endured a difficult January, losing to Sunderland, Manchester United, Liverpool and Everton as injuries to Lescott and suspension to Kompany unsettled the back four.
However, they seemed to have turned a corner when they won every game in February, recording four straight clean sheets into March. That was before defeats away to Swansea and Sporting saw them dumped out of the Europa League and overhauled by Manchester United in the Premier League. Suddenly, City are now in danger of ending the season trophy-less.
Mancini took the blame for Europa League elimination, admitting he got his tactics wrong. "I'm disappointed because I might have made mistakes, and I'm sorry to the supporters," said the City boss. "When a manager doesn't prepare well for the game, this happens. When I lose a game I think about why I lost and think about where I made mistakes."
While such honesty is refreshing, it must be worrying for City fans desperate to secure their first league title since 1968. What Sheikh Mansour must be thinking is anyone's guess. A net transfer spend of £300million must surely win you more than an FA Cup and the Premier League is the only trophy up for grabs for Mancini's men now.
Failure to win that would be difficult for Mancini to explain away. This season Chelsea, Arsenal and Liverpool have been all but out of the title race since Christmas. Tottenham briefly threatened but they face a struggle to even hold on to fourth now. That leaves only Manchester United to beat.
Ferguson's side are nowhere near as strong as they have been in previous seasons and you feel the Scot will strengthen in the summer making it even more difficult for City. Vidic and Ferdinand have missed huge chunks of the season and United's central midfield is certainly weaker than City's, and maybe even Tottenham's. But United know what it takes to win matches, they have the experience of title run-ins that City don't.
Fortunately for Mancini, he has a squad more than capable of winning the league already. A little bit of belief and victory over United on April 30 at the Etihad should be enough to secure Premier League glory. Should they hold their nerve, the experience this year will stand them in good stead for next year's campaign.
The experience of this season's Champions League will also benefit them next year, and, with a kinder draw, they would enter the 2012/13 competition as one of the favourites. Players like Kompany, Silva, Aguero, Yaya Toure and a fully-fit, on-form Tevez would get into any team in Europe, but at the moment they're letting themselves down at the crucial moments.
The opportunity is right there this year to correct that and set them up for a sustained period of domestic dominance. If they can take it they'll be difficult to match over the next few years. If not, Chelsea, Arsenal and Liverpool all must surely come back stronger next year. As for United, if they can beat City to the title with their current squad, the psychological impact on Mancini's men could be long-lasting.