Manchester City 3 QPR 1
With Jose Mourinho, manager of City's Champions League opponents Real Madrid, watching from the stands, the hosts did concede an equaliser to Bobby Zamora in the second half, rekindling memories of the last time the clubs faced each other.
Four months on from that last extraordinary meeting between the sides, in which City's 3-2 victory on the concluding day of last season brought them their first English title in 44 years, Mancini's men took the lead after 15 minutes.
City only had a Yaya Toure strike to show for their dominance when Zamora stunned the champions with a 59th-minute equaliser against the run of play.
City's response was to go back ahead almost immediately, with Edin Dzeko heading home, and while Carlos Tevez added a third in injury time as he stuck out a foot to divert a Dzeko shot past Rob Green, but Mancini was unimpressed.
"I think we played well in first half, but we have one problem at the moment - when we have a chance to score we don't score and the game can change," he said in an interview on ESPN.
"We had this problem in the first game [against Southampton] and against Liverpool.
"In the second half we didn't play well. We were too slow but in the end it's important that we took three points."
Zamora's goal meant that City are still yet to keep a clean sheet in the Premier League this season - a hallmark of their title run last season - although captain Vincent Kompany is unconcerned just yet.
"No it doesn't matter. We've always proved to be solid come difficult times," said the defender.
"Come December, January and February we'll show it. At this time everyone tries to play the game nicely.
"We left ourselves exposed but at the end of the season we won't do that."
Kompany did admit his side's inability to kill QPR off early on was a problem to be rectified in the more immediate future.
"I think probably we worked really hard to keep possession and create chances and if after a while you don't score your chances you let other team into the game," he said.
"It just seems to be one of those things. They didn't have any chances before that - one shot on goal and we were unlucky with the deflection.
"But we showed how much character we have. We seem to cope well with any downs we have."
QPR defender Ryan Nelsen twice came close from set pieces, his bicycle kick flying beyond the far post and then the New Zealand international slid in and almost converted Esteban Granero's free kick.
But Argentina striker Tevez completed the scoring in the 93rd minute when he deflected Dzeko's wayward strike past the wrong-footed Green.
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