Manchester City boss Pep Guardiola said his side lacks composure to defend a lead after Real Madrid struck twice late on to snatch a 3-2 win from the first leg of their Champions League play-off.
City have dipped drastically from the high standards they have set during Guardiola's glorious nine-year reign this season, with the concession of late goals a repeated issue.
The English champions have conceded eight times in the last 15 minutes of their last five Champions League games to also blow leads against Feyenoord and Paris Saint-Germain in the league phase.
This time it is likely to be fatal for their chances of reaching the last 16 as the holders head back to the Santiago Bernabeu in a commanding position for the second leg on February 19.
"I am not good enough to give the composure to the team to manage this situation," said Guardiola. "The truth is we are not stable enough. It happened many times."
Erling Haaland had twice given City the lead at the Etihad, either side of Kylian Mbappe's equaliser for the Spanish giants.
But City were undone by a catalogue of defensive errors to throw away the lead in the closing stages.
Ederson compounded a poor clearance by parrying Vinicius Junior's shot into the path of Brahim Diaz to equalise.
Vinicius then took advantage of hesitant defending from Rico Lewis to race clear on goal and Jude Bellingham tapped home the Brazilian's wayward effort into an unguarded goal.
"After the 2-1, it happened like it happened this season many times against Feyenoord, Sporting Lisbon, Brentford, Manchester United.
"In the end we gave it away ourselves and at this level it's so difficult. It's not the first time."
'ANGER AND FRUSTRATION'
City defender John Stones said Guardiola had called for more accountability from his star-studded squad to dig themselves out of a rut.
"It's a feeling of anger and frustration," said Stones.
"We need to see games out better. The manager said we need to take accountability for what we do on the pitch.
"We need to step up when these bad moments happen.
"Today we had a great opportunity to go to the Bernabeu with a 2-1 lead."
The sides are meeting for the fourth consecutive season in the Champions League.
Madrid have won two of the previous three ties with the winner on each occasion going on to lift the Champions League.
However, in stark contrast to their previous visits to the Etihad, where City dominated, this time Madrid had the majority of the chances.
Mbappe, Bellingham and Vinicius had been guilty of being uncharacteristically wasteful in front of goal until the late twist in the tale.
"It was a very good performance from us. We have to be content with the result as well even though we had lots of opportunities," said Ancelotti.
"We didn't deserve to be 1-2 down. We were really dangerous but in the end the win is deserved."
Victory was even sweeter for the 15-time European champions as they travelled to Manchester without their entire first-choice defence.
David Alaba, Antonio Rudiger, Eder Militao and Dani Carvajal were missing, forcing midfielders Aurelien Tchouameni and Federico Valverde to line up in the backline alongside youngster Raul Asencio.
"The four defenders, who never played together before, were able to play a good game because the team worked really well defensively," added Ancelotti.
"The more emergencies there are, the more this team sacrifices. I didn't think in this moment the team was capable to sacrifice like this."