This year is only the second time that the current Premier League champions have been part of the tournament having been knocked out of the group stages last season.
"This group is very difficult but we have four games," said Mancini. "Ajax play fantastic football but they have a young team.
"It's difficult to play away, and it's clear that we can lose our chances [of qualifying], but we need to do our best.
"We don't have experience as a club but all our players have experience in the Champions League. Maybe as a club we need to get experience in the Champions League, but we have players with that experience."
City face Ajax on Wednesday night in Group D.