After enjoying such a sensational start to the campaign, City are finally experiencing a significant wobble. Dumped out of the Champions League by Napoli, the Blues were on the wrong end of a comeback win by Chelsea at Stamford Bridge despite getting off to the perfect start thanks to Mario Balotelli.
However, Mancini was defiant, saying: "At this moment, we should be very strong."
Strange as it may have appeared a couple of weeks ago, City might have been knocked off top spot by Manchester United when they walk out to face in-form Arsenal at the Etihad Stadium on Sunday.
That in itself would bring added pressure to Mancini and his men, who remain odds-on favourites to clinch their first championship since 1968.
The Italian added: "It is at these moments that you become stronger, as players and a team. For this reason, the result is a lesson for us."
Given their previous performances last term, and how they played for 25 minutes on Monday night when they could easily have swept Chelsea away, it is hard to be too critical of City.
However, there were echoes of the Champions League defeat to Bayern Munich in September, when City were also the better side, only to crumble when the going got tough.
On this occasion, the Blues can justifiably point to the failure of referee Mark Clattenburg to spot a clear trip on David Silva when they were ahead and on top, plus the dismissal of Gael Clichy, as the major turning points.
"If the Silva penalty had been awarded, probably the game was finished," said Mancini. "After the sending off it was a different match."