City were handed a crushing defeat with the very last kick of the game as Ji Dong-Won gave Sunderland a dramatic 1-0 win at the Stadium of Light deep into injury time.
The Blues dominated the match from start to finish and struck the bar twice, but just couldn’t find a way through the packed home defence to complete a miserable holiday period for the Premier League leaders who have now gone almost four hours without a goal.
Though City stay top, the chance to go three points clear went against a team who have now beaten the Blues twice in successive seasons with injury time goals on their own patch.
In came Edin Dzeko, Adam Johnson, Aleks Kolarov, Nigel de Jong, Joleon Lescott and Gareth Barry and while it was understandable to see David Silva and Sergio Aguero on the bench, the fluidity of the Blues’ attack was bound to be affected.
That’s not to say the starting XI wasn’t formidable, but with the previous day’s slip-ups by Manchester United, Tottenham and Chelsea, City needed to take full advantage of the unexpected bonuses delivered by Blackburn, Swansea and Aston Villa respectively.
The hosts, buoyed by the arrival of the recently-appointed Martin O’Neill, began with a makeshift back four having lost three defenders to injury, yet they still should have gone ahead after just three minutes when Nicklas Bendtner was put clean through but couldn't convert his one-on-one with Joe Hart.
It was to be Sunderland’s only real chance of the first half as City settled into the game gradually and then began to turn the screw with Johnson in particular causing full-backs for the day Colback and Gardner all sorts of problems – the England winger seems to relish playing his hometown team.
Collectively, the final pass in front of goal was the main reason the Premier League’s highest scorers reached the halfway point goalless – despite Dzeko shaving the bar with a fierce effort – but there was a feeling of inevitability about the pressure City were exerting.
With Mancini feeling more urgency was needed in the final third, Aguero was introduced for the start of the second half in place of the yellow-carded De Jong as the Blues signalled their intent on leaving the north east with maximum points.
Silva was sent for just ten minutes later as the City looked to up the ante, urged on by their concerned boss.
With Sunderland increasingly reduced to defending with nine men behind the ball as City probed in familiar fashion, it became evident that just one flash of genius could settle what was increasingly becoming a one-sided affair.
That said, Stephane Sessegnon could have given the Black Cats an undeserved lead on 64 minutes after sloppy defending allowed the Beninese striker a clear scoring chance almost out of nothing, only for his effort to flash narrowly wide with just Hart to beat.
It was a wake-up call for City, if nothing else, but not one they would heed and just as had happened at The Hawthorns, the Blues’ attacks were becoming increasingly desperate.
More worryingly, the guile and craft City have unlocked defences with all season looked to have deserted them for a second successive game – or have opposing teams just worked out that it is possible to defend for 90 minutes and take a point - or perhaps more - even if it is on their own turf?
City's last chance to claim victory came in the dying seconds of normal time in a frantic finale. Silva’s shot was parried up and Micah Richards headed against the bar with the goal at his mercy and it was clear it wasn’t going to be the Blues’ day.
Then Sunderland broke for one last attack and as the City midfield laboured to get back, Sessegnon played in the marginally offside Ji Dong-Won who rounded Hart and stabbed home the winning goal to the disbelief of all in the 40,625 crowd - proof of how cruel football can sometimes be.
Now City must bounce back with a win against Liverpool following a weekend of shock results that the Blues have now reluctantly become part of.