Roberto Mancini accepted it would take a 'miracle' for Manchester City to reach the Champions League knockout stages after defeat at Ajax.
The Premier League champions were outplayed in Amsterdam as they surrendered a lead to slump to a 3-1 loss that left them bottom of Group D at its midway point. Even though City were in front through a fine Samir Nasri strike in the Dutch capital, it came against the run of play and they were stung as the hosts hit back through Siem de Jong, Niklas Moisander and Christian Eriksen.
City next face Ajax again at the Etihad Stadium in a fortnight before hosting Real Madrid and then travelling to Borussia Dortmund.
"It is very difficult to qualify now," Mancini said.
"It would be a miracle." Mancini sought to deflect attention from his under-performing players by blaming himself for the loss.
The Italian said: "It is my fault. I didn't prepare well for the game and I take the blame.
"I thought in one way and it was different. When you prepare in one way and it is a different game, it is difficult.
"We had more chances to score and in the Champions League you need to score. It is my fault, I repeat." Mancini was similarly self-critical after damaging losses to Everton and Sporting Lisbon last season. The City boss varied his tactics and formations throughout in search of the win his team needed to revive their Champions League campaign. The game ended with multi-million-pound strikers Carlos Tevez, Mario Balotelli, Sergio Aguero and Edin Dzeko all on the field in a four-pronged attack but it proved to no avail. The defensive line was also varied between three and five men and Gael Clichy was in an unfamiliar centre-back's role when he deflected Eriksen's strike past Joe Hart for the third goal. Defender Micah Richards told Sky Sports: "It's not something that we've worked on a lot. We're just used to a back four.
"But the manager likes it and if we want to do well with it then we'll have to work harder on it. "It's a hard system and I think the players prefer a 4-4-2 but he's the manager and we'll do what he says." Mancini did not feel the changes of approach should have derailed his side. He said: "We changed for five minutes to three at the back, but we always have 11 players.
"I don't think that is important - three, four, five, six or seven defenders.
"If someone wants that as an excuse then okay, but it's not the reason."
Dortmund top the group with seven points after beating Real Madrid, who are behind them on six. Ajax's victory lifts them to three - two points above City. "Although City had chances I think we deserved to win this game," Ajax coach Frank de Boer said. "This is the way we want to play football and I am proud of the team."