Midfielder Samir Nasri struck the 80th-minute winner against Southampton after the City faithful had been dragged through the wringer yet again, in contrast to Chelsea fans who saw their new signing Eden Hazard engineer an easy 2-0 win at Wigan Athletic.
The game started badly for City when their top scorer last season Sergio Aguero, who netted the dramatic late winner as they beat Queens Park Rangers 3-2 to win the title in May, was carried off with a knee injury early on.
A tired-looking David Silva then had a woefully weak penalty saved before a slimline Carlos Tevez, having won the spot-kick after a good turn foxed Jos Hooiveld, avoided the offside flag to score at the near post in the 40th minute after Nasri's pass.
Tevez fell out with coach Roberto Mancini last term after refusing to warm up as a substitute in September but was drafted back in towards the end of the campaign and has lost weight during pre-season to look extra sharp.
City's defence was far from it after the break and promoted Southampton, back in the top flight for the first time in seven years, found themselves in front after carbon copy sidefoot finishes from substitutes Ricky Lambert and Steven Davis.
Abu Dhabi-backed City, who spent millions to help secure their first top flight league title since 1968, handed a debut to new signing Jack Rodwell from Everton but his mistake set up a counter-attack for Davis' goal.
Edin Dzeko, just like he had done against QPR three months ago, grabbed City's equaliser following a corner and poor defending from the visitors allowed Nasri to slam in the winner.
"It's like the last game of the season so we started the same and I hope at the end it will be the same result for us," a smiling Nasri told Sky Sports.
"It was a difficult game against a good squad in Southampton who played really good football."
The opening weekend of the Premier League has been packed with excitement to silence those who thought the recent successful London Olympics would dull the impact of football's return to the English consciousness.
Chelsea's Hazard, widely hailed as the next big thing, lived up to all the hype inside the first seven minutes of his league debut by setting up both goals.
The Belgium playmaker, who joined the European champions from Lille in the close season having turned down City and Manchester United, quickly proved wrong any doubters who suspected England would be far tougher than the modest French league.
First he expertly turned marker Ivan Ramis to release right-back Branislav Ivanovic, who ran in and coolly slotted home in the second minute having been allowed to play despite a red card in the 3-2 Community Shield loss to City last Sunday.
Hazard then danced his way into the box and was carelessly upended by error-prone Wigan debutant Ramis, leaving Frank Lampard to slam in the seventh-minute penalty.
Like the hit-and-miss Fernando Torres, Hazard's level dropped after the break and he w
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