The Italian bad boy saw red in the 36th minute for an outrageous chest-high challenge on Dinamo Kiev's Goran Popov.
It gave City a mountain to climb after losing 2-0 in the first leg in Ukraine.
And although they pulled one back through Aleksandar Kolarov, the Eastlands men could not turn the last-16 tie around.
City chief Mancini said: "It's a problem because Mario can be a fantastic player.
"But when he does stupid things like tonight it's difficult for me, for him and the team. Am I angry? What do you think?
"I didn't see the foul but I'm disappointed because this was a difficult game and you can't have a stupid red card like this.
"It was tough but if it had been 11 v 11 we would have scored two or three goals.
"With one player less and two goals down it became very difficult. But the other 10 were fantastic for 60 minutes.
"Is he a frustrated man? I hope so because with 11 we would have gone into the quarter-finals."
Mancini hinted he may axe Balotelli from his squad for Sunday's showdown at Chelsea.
The pair are likely to have talks at Eastlands today but Balotelli's red-mist moment left supporters fuming.
And there were claims he clashed with a group of Kiev fans outside the ground after the game.
City defender Vincent Kompany added: "It's difficult to comment on what happened but with 10 men it is difficult."
Seeing red: Mario Balotelli made his side's task all the more difficult with a silly red card in the first half
Super Moron to the rescue of Man Silly.
Fatigue for them????
aiyo thot they has many striker?
1 lost nia
not whole striker lost nia
Originally posted by Bus&Soccer l0v3r (VO3x 1):aiyo thot they has many striker?
1 lost nia
not whole striker lost nia
The problem is, clever Mancini loan out or sold those strikers! Bojinov, Bellamy, Caceido, Santa Cruz, Adebayor are all gone at least for the season. Maybe they can depend on Jo.
Originally posted by CKeer:The problem is, clever Mancini loan out or sold those strikers! Bojinov, Bellamy, Caceido, Santa Cruz, Adebayor are all gone at least for the season. Maybe they can depend on Jo.
Jo?
i dun even think he suit man city shirt