City suffered a 2-1 defeat at Hull on Saturday and are three points behind fourth-placed Liverpool.
“Yes, I was angry after the Hull match,” said Mancini. “This is normal after this kind of game. But I am more confident than before about the Champions League. In my first three or four games, we played very well but we had very few players available.
“I am confident when I have all of the squad available we can win at home and win away. You must remember that we have two games in hand. If we win both of these games, we will be just two points behind Arsenal.
“I think Tottenham, Liverpool, Aston Villa, Manchester City and Arsenal are all fighting for two places in the Champions League. When I have all the players back, we will be better. We have to be really confident.”
