The Citizens boss has highlighted January as a potentially season defining period, with a busy fixture schedule that will be made even harder by the impending departure of influential midfielder Yaya Toure.
The 28-year-old Ivorian international heads off for African Cup of Nations duty with brother, and City teammate, Kolo Toure, after this weekend's FA Cup clash with Manchester United.
Yaya was on the scoresheet in last night's 3-0 victory over Liverpool at the Etihad Stadium, helping City re-establish their three-point lead at the top of the Barclays Premier League table, further highlighting how big a miss he will be in the coming weeks.
"This month without Yaya or Kolo when we play every three days that will be hard," confirmed Mancini. "January is a very crucial month for us because if we can stay on the top after January we have a big chance to win [the league]."
Reflecting on the Christmas period which threw up a number of surprising results, and meant that numerous sides at the top dropped points, Mancini now believes City are locked in a three-way race for the title.
"I think United are a strong team but we should think only of trying to win every game if possible and at the end we will see what happens," he added.
"Tottenham are also very close but I hope we stay there [at the top of the table] for a long time."