Mancini was hired by the club's mega-rich Abu Dhabi owners in 2009 to turn City into serious contenders for silverware on a regular basis and the suave Italian did just that.
A first league title for 44 years, an FA Cup and three consecutive qualifications for the Champions League made City into a soccer powerhouse and there will be no shortage of world-class coaches joining the queue to take over the hot seat vacated by Mancini.
So while City fans were waking up with their club in a state of turmoil - a stark contrast to the smooth transition of power at Manchester United where the retiring Alex Ferguson will be replaced by David Moyes - the current malaise is a million miles away from the dark old days when the club were a laughing stock.
In the 1980s and 1990s, events at City resembled a soap opera.
The managerial revolving door was in danger of flying of its hinges as a procession of so-called saviours came and went.
Howard Kendall, Peter Reid, Brian Horton, Alan Ball, Steve Coppell all tried and failed to revive the club and each failed, leaving the club back on square one.
In 1999, with the club haemorrhaging money, they slid into the third tier of English football and even the most wildly-optimistic sky-blue-blooded fans could not have envisaged a Premier League title little more than a decade later.
Kevin Keegan and Sven-Goran Eriksson made some small steps forward but now, thanks to hundreds of millions of pounds' worth of investment from Sheikh Mansour's Abu Dhabi United Group since 2008, City are in rude health despite a sobering season.
While their defence of the title was feeble and the FA Cup defeat by Wigan Athletic humiliating, they remain the second-best team in England, are immaculately run and have a new youth academy that will rival any in the world and a squad of players that would be the envy of most clubs in the world.
With the prospect of some major signings in the off-season, City will almost certainly be battling for silverware on multiple fronts next season.
However, the next few days and weeks will be vital if the club are to build on the foundations already in place and regain the momentum that Mancini allowed to seep away.
The competition could be even harder next season with Jose Mourinho favourite to return to Chelsea, Arsenal threatening to open their cheque book and champions Manchester United eager to back new manager Moyes with a large transfer kitty with which to forge his identity.
City's owners have called for a change of direction - a more holistic approach they describe it as - and key to their vision and the hopes of creating a stable environment will now be hiring the right manager to replace Mancini.
Whereas in the past the City job came with a health warning, the current set-up looks enticing for the right man.
Manuel Pellegrini, Mourinho and Rafa Benitez have all been linked to the job but Pellegrini is the favourite despite the Malaga coach denying that he has already been approached.
His diligent work at the Spanish club, on a limited budget, has made him one of the most sought-after coaches in Europe.
Mancini was often accused of tactical naivety, especially in the Champions League where City's two campaigns have ended in abject failure, while Pellegrini's thoughtful and flexible approach has already achieved European success.
He took unfashionable Villarreal to the Champions League semi-finals and steered cash-strapped Malaga to this year's quarter-finals.
City are desperate to avoid a return to the manic days of old and are seeking an identifiable playing style to replace that of Mancini who occasionally looked uncomfortable allowing his playmakers to flourish.
Mancini will forever by loved by City's fans but ultimately he proved incapable of continuing the momentum created by last season's title triumph.
His sacking, while badly handled and humiliating for a man who dragged City out of the shadow of United, is unlikely to send the club careering back into chaos and providing they choose their next move wisely, this season may just go down as a blip in City's onward march.
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