Three goals in 11 first-half minutes helped Manchester City sweep aside Sunderland 4-1 at the Etihad but captain Vincent Kompany's return from injury lasted only nine minutes to take the gloss of the victory.
Raheem Sterling, Yaya Toure and Wilfried Bony all struck in the opening 23 minutes before Kevin De Bruyne got in on the act early in the second half when Kompany was still on the bench.
City's defensive fragility without the skipper was evident once more, though, as Fabio Borini's effort denied them a clean sheet - the 10th time in the Barclays Premier League they have failed to shut the opposition out when their captain has not been present.
And although Kompany was brought on for his first appearance since November 8 shortly afterwards, that comeback proved to be short-lived as the Belgian was forced off again after appearing to injury himself when he tried to poke the ball away from Borini.
It casts his availability for the clash at high-flying Leicester on Tuesday in doubt and City then travel to Watford, Everton and Norwich in a tricky run of four successive away games.
Like Kompany, Sergio Aguero started on the City bench, but it was Sunderland's starting line-up that included more surprises.
Forwards Danny Graham, Steven Fletcher and Borini all started and Vito Mannone was selected ahead of ex-City goalkeeper Costel Pantilimon for his first Premier League start of the campaign.
It proved to be a decision that backfired as Mannone was beaten on three occasions early on.
Sterling had earned an early caution for diving when he cut past Billy Jones in the area, but the full-back was not close enough to stop the England international breaking the deadlock after 12 minutes with a header from De Bruyne's fizzing right-wing cross.
Mannone was picking the ball out of his net again five minutes later when Toure trotted forward and steered a 25-yard left-foot try into the far corner, a nd it was 3-0 soon afterwards as De Bruyne's free-kick was glanced beyond the hapless Mannone from 15 yards by Bony's downward header.
However, City did once again look shaky at the back in Kompany's absence and Graham should have scored when heading wide, while Joe Hart was forced into his only save of the half from Borini.
Mannone managed to stop one effort early in the second half from David Silva after a clever flick from the brilliant De Bruyne, who was soon on the scoresheet himself before the hour.
He had intended to tee up Bony and although Sebastian Coates' slide tackle took the ball away from him, it rolled into the Belgian's path and left him with a simple finish for his 10th City goal.
The home side were able to introduce Kompany just after the hour, yet only after they conceded once again without him on the pitch. Substitute Lee Cattermole's scuffed shot found its way through to Borini and, at the second attempt, he beat Hart at the near post
Kompany was then introduced to cheers from a record attendance and he did hang around long enough to see Bony blaze a penalty over after Silva was tripped by Coates, seemingly outside of the area.
That crowd then fell silent as Kompany's number four was flashed on the fourth official's board when Martin Demichelis came on with 19 minutes to go, and the captain shook his head before heading straight down the tunnel with home fans once again fearing the worst.
TWEET OF THE MATCH
@markbooth_mcfc: "Heartbreaking for Vincent. Made perfect sense to give him some minutes in this low pressure situation but the man has no luck at the moment." A mixed afternoon for Manchester City.
Joe Hart: 6
Bacary Sagna: 6
Eliaquim Mangala: 6
Nicolas Otamendi: 6
Aleksandar Kolarov: 6
Yaya Toure: 8
Kevin De Bruyne: 9
David Silva: 9
Raheem Sterling: 8
Wilfried Bony: 7
Vincent Kompany: 4
Fabian Delph: 6
Martin Demichelis: 6
Vito Mannone: 4
Billy Jones: 4
Sebastian Coates: 4
John O'Shea: 4
Patrick van Aanholt: 4
Adam Johnson: 5
Yann M'Vila: 6
Jordi Gomez: 5
Fabio Borini: 7
Steven Fletcher: 5
Danny Graham: 6
Lee Cattermole: 5
Jeremain Lens: 5
Duncan Watmore: 5
Kevin De Bruyne. There were a number of outstanding candidates on the City side but the Belgian caught the eye throughout. He was full of running, his crosses were dangerous and hit the target, and his general passing and vision were excellent. He was involved in a lot of City's good work and claimed a deserved goal in the second half.
MOMENT OF THE MATCH
City pieced together a number of good moves throughout of the match and might have been rewarded with more goals than they managed. One such move that did not bear fruit came early in the second half as De Bruyne picked out a brilliant run from David Silva with an inch-perfect rabona-style pass. Silva's shot looked to be curling inside the far post but Vito Mannone produced a fine one-handed save.
VIEW FROM THE BENCH
This was just what City boss Manuel Pellegrini required - injury to Vincent Kompany aside - after the frustration of Monday's loss to title rivals Arsenal. Admittedly Sunderland were poor, but his side did not lack motivation and were at their destructive best in attack - and it is probably a bonus that they did that without Sergio Aguero. There were occasional moments of worry in defence, but Pellegrini always says that matters little if the rest of the team are functioning. For Sam Allardyce, this was one to write off. There is still plenty of time for his side to haul themselves out of trouble but they are starting to slip behind and performances like this will drain confidence.
MOAN OF THE MATCH
The attendance of 54,523 was a record for the recently enlarged Etihad Stadium and the fans were in a good mood from the off after what proved a popular unveiling of the club's new badge. The team lived up to expectations too, delivering a fine performance. Sadly the atmosphere was killed by Kompany's injury. The Belgian, coming off the bench after eight games out, had been on the field just nine minutes when he trudged off, apparently injured again. His shake of the head said it all, and the crowd were stunned into silence. It ruined what had been a good day for City.
WHO'S UP NEXT?
Leicester v Man City (Barclays Premier League, Tuesday, December 29)
Sunderland v Liverpool (Barclays Premier League, Wednesday, December 30)