The City boss held his hands up for his failure in preparation ahead of Wednesday night's shock 3-1 Champions League defeat to Ajax in Amsterdam.
He still accepts responsibility for a result that leaves the Blues requiring a "miracle" to avoid tumbling out at the group stage for the second successive season.
However, what he will not acknowledge is any weakness in formation.
Having toyed with three at the back at various times during the current campaign, Mancini did again in midweek as he desperately sought a way back into the contest.
The move had catastrophic consequences, leaving substituted Joleon Lescott fuming, Gael Clichy appealing for guidance about exactly where he was supposed to be playing, City conceding a third goal and Micah Richards conducting a post-match interview where he confirmed his team-mates were ill at ease with the tactical switch.
Mancini claimed Richards' comments were "not important".
However, his assessment of the situation left little room for argument.
"Good players should be able to play in any system," said Mancini.
"If you are a top player, the system is not important. If you don't understand you are not a top player and you cannot play for a top team.
"Maybe Micah doesn't know this because it is his first game. He has been out for two and a half months and has worked less than the other players.
"Maybe the next time we play this system Micah can stay on the bench and we will play with another player.
"But what Micah said is not important. He answered one stupid question."
The general consensus is that Mancini was only tempted by the three-man defensive idea during the summer, as he sought a way to get the best from a title-winning team he still felt required improvement.
Mancini disputes this version of events.
Indeed, if the Italian is to be believed, he has used the system far more than anyone previously thought.
"In pre-season we only had 10 senior players," he said, ahead of Saturday evening's encounter with Swansea at the Etihad Stadium.
"But I wasn't changing anything. It is difficult to watch from the stand when we change the system but we have used this a lot of times during games last season, a minimum of 50 times.
"We were 2-1 down and we wanted to improve the situation.
"With this system we beat Chelsea 3-2 in the Community Shield. With this system we recovered from 3-0 down against United, got back to 3-2 and had a chance to draw with only 10 players.
"With this system we have changed the result every time."
Not this time though, as City's previously watertight defence continues to leak goals.
They have now conceded 22 goals in 13 games in all competitions, eight fewer than the time it took last term.
City have a single clean sheet to their name, compared to five at the same stage 12 months ago.
"The problem is that we are continuing to concede too many goals," said Mancini.
"In the Premier League you have a chance to recover because the season is long. In the Champions League no. If you have a chance to score or close the game out you should."
It would take a remarkable turn of events for City to change their European fortunes now.
Almost certainly, they will need to win their remaining three games and even then might require other results to fall for them.
Mancini remains confident in their abilities though, and refuses to believe they will not respond.
"You think we can go down after one defeat? I don't think so," he said.
"We are strong enough for this.
"Any team can lose a game. It is important we understand why and what mistakes we made.
"From this we can improve and maybe in the next game we won't make them again."