City plundered 102 goals as they streaked past a faltering Liverpool in last season's title race, but Monday's 2-1 loss at Crystal Palace left their defence of the trophy in pieces.
Nine points behind leaders Chelsea having played a game more, Manuel Pellegrini's side need a minor miracle to retain the title and now face a fight to avoid a place in next season's Champions League play-off round.
The club's previous title triumph, in 2012, was followed by a similar slump.
Having snatched the crown from Manchester United's grasp on the final day of the 2011-12 campaign, City stagnated and finished the following season 11 points adrift of their derby rivals in second place.
Manager Roberto Mancini paid the price with his job, sacked two days after a shock defeat by Wigan Athletic in the FA Cup final, and a similar fate may lie in store for Pellegrini.
Heralded as the antithesis to the spiky and combative Mancini, the urbane Chilean steered the club to a league and League Cup double in his first season.
But Pellegrini's position now appears under serious threat, with British bookmakers offering odds of 2/7 that he will no longer be at the helm on the opening day of next season.
Former United manager Alex Ferguson accused City of slackening off after their 2012 league success in his autobiography and it is a charge that his former captain Gary Neville repeated on Monday.
“They have got a mentality problem, there is no doubt about that. This team cannot sustain success, and I think that is a terrible thing to have levelled at you,” said Neville, now a television pundit.
“When you win championships, you have got to be able to come back again with hunger and they do not. They get to the top of the mountain and drop off it.”
The club's failure to reach the Champions League quarter-finals also counts against Pellegrini, even if there was no disgrace in succumbing to the genius of Barcelona's Lionel Messi as City did in the last 16.
But while Pellegrini is expected to carry the can for City's failure to kick on, fingers are also being pointed at figures higher up in the Etihad Stadium hierarchy.
It is CEO Ferran Soriano and director of football Txiki Begiristain who are responsible for the club's transfer activity, not Pellegrini, and the club's close-season dealings left much to be desired.
Despite Financial Fair Play restrictions, City splurged £32 million ($47.6 million, 43.8 million euros) on Eliaquim Mangala, but the French centre-back has been unable to hold down a first-team place.
Fernando, Bacary Sagna and Willy Caballero have added little beyond squad depth and it says much that it was 36-year-old Frank Lampard, supposedly on the brink of semi-retirement in Major League Soccer, who had made the biggest impact by the time Wilfried Bony arrived from Swansea City in a Â£25 million deal in January.
“I think it is so poor from those at the top of the club,” said former Liverpool defender Jamie Carragher, Neville's fellow pundit on Sky Sports. “It is mismanagement from them.”
Compounding matters, City's stalwarts have struggled to recapture the heights of last season.
While Joe Hart has impressed, Sergio Aguero has scored only three league goals in 2015, the influence of Yaya Toure and David Silva has diminished and captain Vincent Kompany appears to be in terminal decline.
Arsenal and United have both exploited City's difficulties to surge past them and on Sunday the champions face a potentially chastening trip to Old Trafford.
With a seven-point advantage over Liverpool, a top-four place does not appear to be in jeopardy, but a fourth-place finish would represent another damning fall from grace. – AFP
Original source: Deja vu for City fans