City began the competition with much higher hopes and, given their resources, outside expectations were also greater but Mancini insists he is not embarrassed by the situation.
He said: "Embarrassment for what, I don't know, but we are disappointed because we wanted to go to the second stage this year.
"I think in football you need to learn. If there are other teams that play better than you and deserve to go through, we should accept this.
"If we didn't play well, Borussia and Real Madrid played better than us - we should accept this and we will try better next year."