City had suffered a 1-0 defeat in Portugal, and Mancini’s side looked set to be eliminated from the competition after first half goals from Mathias Fernandez and Ricky van Wolfswinkel put the visitors 3-0 up on aggregate.
But the Premier League outfit fought back in the second half as Sergio Aguero scored a brace and Mario Balotelli netted a penalty to edge City ahead on the night – but the home side were unable to find the crucial winner.
“I’m disappointed because I might have made mistakes, and I’m sorry to the supporters,” said Mancini. “The players did everything, and fought on the pitch.
“When a manager doesn’t prepare well for the game, this happens. When I lose a game I think about why I lost and think about where I made mistakes.”
Mancini appeared to argue with Balotelli after the Italian striker conceded a 33rd minute free-kick which was converted by Fernandez.
But the 47-year-old refused to blame the striker after the defeat – and admitted it was City’s lacklustre first-half performance that cost his side a quarter-final place.
“I think the first half was very strange,” he added. “We left them too much space on the counter-attack and didn’t play as a team. We expected the counter-attack and didn’t do a good job in the first half.
“We could have scored the fourth after scoring three.
“I was disappointed [with Balotelli] after conceding the free-kick, but sometimes it is my fault as the manager, not the player’s fault.”
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