Their debut in the world's most prestigious and lucrative club competition has failed, with their Champions League campaign so far dogged with controversy and lacklustre performances.
Whilst the players, especially Carlos Tevez, are to blame for the most part, it's ultimately the manager who has to take the bullet.
So here's how Roberto Mancini got it wrong in the Champions League.
That fateful night in the Allianz Arena doomed Manchester City's Champions League prospects, with more than just a 2-0 defeat doing harm to City's European ambitions.
Whilst Carlos Tevez should not have refused to play, Roberto Mancini probably should have tried a lot harder to keep it behind closed doors.
By making the whole saga public, pressure and media scrutiny intensified every time City subsequently took to the pitch, especially in the high-pressure stakes of the Champions League.
In the Premier League, City's stunning play and scintillating form meant they weren't shackled by extraneous factors, but in the Champions League, it was a different story altogether.
Poor form, several rumours of dressing room content, more focus on City falling apart and the players being dismissed as European no-hopers meant every Champions League game was the biggest psychological battle of City's season.
The outside pressure, not dealt with adequately by Roberto Mancini and his public comments, meant Manchester City were always going to subsequently be at a disadvantage before a ball was even kicked.
The lack of urgency in Manchester City's Champions League play has had deleterious effects on their Group A fate.
Take the 2-1 defeat away to Napoli, for example. City had 70 percent of the possession and a 91 percent pass accuracy rate, compared to 73 from their opponents.
But from all that keep-ball, they managed only four more shots than their opponents, and only three more on target.
After Mario Balotelli equalised following Edinson Cavani's opener, City dominated the first half and looked most likely to win.
What happened after the break? They conceded within four minutes and went on to lose. There was no urgency in their play and no changes for another 20 minutes after Napoli took the lead.
A sense of "we've got the better players, we'll score eventually" seemed to envelope City and the manager, as was the case at home to Villarreal when Sergio Aguero bailed the team out with an injury-time winner.
This time, though, it wasn't the case, and nor was it in the 1-1 draw at home, costing City five points, and most likely, a place in the knockout stages.
In the Premier League, Roberto Mancini has got his Manchester City men playing like a slick, well-oiled machine.
In the Champions League, however, there is no such cohesion.
Perhaps it's because they're on a bigger platform and want to prove their worth to the watching world, but City's players seem a bit more greedy in Europe.
Too many players going on solo runs, not enough passes, too many individual efforts on goal, there just isn't the cohesion that's evident in the marathon of the Premier League.
Mancini probably should have devoted more time to developing City's game-specific tactics in the Champions League.
In their opening Champions League game against Napoli, a much fancied Manchester City struggled to a 1-1 draw.
In their second game away to Bayern Munich, the swagger they tried to install on the game was quickly deleted by Mario Gomez.
The only match City have played with swagger and done well was against Villarreal, who are bottom of the group and had five key players out for that match, including star player Bruno Soriano.
And in that away game to Napoli, City's belief in their own ability as players was merely rewarded with a 2-1 defeat, partly due to the lack of hard work they put in to follow up that self-confidence.
It seems if there's one thing Roberto Mancini has failed at more than anything in the Champions League, it's safeguarding his team from the corrosive tentacles of complacency.
As Manchester City have become a more exciting, attacking outfit this season, they've also become more one-dimensional.
Roberto Mancini has set his side up to, most often than not, attack from the wings and defend though the middle, with his full-backs—especially Micah Richards—given more license that ever to join the fun in the final third.
This style damages teams in their typically weakest areas, with City players closing down opponents to make them channel their play through the middle facing City's best defensive area, the two centre-backs.
However, it's a style of play that never changes, meaning City are more vulnerable than they need to be in the Champions League, with the Bayern Munich and Napoli teams who are among the best in Europe at exploiting gaps on the wings.
If Manchester City are to succeed in the Champions League in the future, Roberto Mancini needs to concentrate on his opponent's game, not just his own.