Mancini believes the ability to switch between such a potent frontline will be key for the battles ahead.
"We changed against Norwich because we played three games in six days and needed to have fresh players, but we are sure that all of our strikers can start to score like they did here," he said.
Edin Dzeko was recalled to the starting XI at Norwich on Saturday and repaid his manager's faith with a quick-fire brace to put the visitors 2-0 up inside four minutes.
Carlos Tevez was left warming the bench at Carrow Road, but could come back into contention for the home game with Stoke on New Year's Day.
Mancini added: "We have won games with Carlos and Aguero, Edin and Carlos, Aguero and Edin; all these three players, if they work hard like this, they can score important goals for the season."
The City boss insists the current seven-point gap to United is "not a problem", bearing in mind the position from which City went on to beat their fierce rivals in the dramatic conclusion to last season.
And Dzeko believes "nothing is finished" after feeling he went some way to proving a point against Norwich.
"It is not the first time, but the manager gave me the chance to play and I think I paid him back," Dzeko said. "We will see what the future brings."