Pep Guardiola said he was “not good enough” to find a solution to Manchester City’s woes after they conceded two late goals to slump to a 2-1 home derby defeat to rivals Manchester United.

City had led through Josko Gvardiol’s 36th-minute header but rarely looked comfortable in the game and it all unravelled in stunning fashion at the death.

Matheus Nunes, asked to fill in at left-back, was guilty of a poor back-pass and then fouled Amad Diallo trying to make amends to concede a penalty which Bruno Fernandes converted in the 88th minute, and two minutes later Diallo found space to latch on to a long ball and score the winner.

It was an eighth defeat in 11 games for City as their crisis continued to spiral, and Guardiola admitted he cannot find the answers.

“I’m the boss, I’m the manager, I have to find solutions but I don’t find solutions,” Guardiola said.

“This is a big club and when you lose eight of (11) something is wrong. You can say the schedule is tough or the injuries to players, but no.

“I’m the manager and I’m not good enough, simple as that. I have to find a way to talk to them, to train them in the way we need to play, to press the way we need to press. I’m not good enough. I’m not doing well. That is the truth.”

Guardiola signed a new two-year contract in November at a point when City had lost four in a row, saying he did not feel he could leave the club at a difficult time.

Now he is facing questions as to how – and when – he can stop the rot.

“I’m here,” he said. “I’m responsible. It would be easy for me to say we lost because of this action or this player or this situation but football is a team.

“I’m completely convinced in what I’m saying, that I’m not good enough to find a way for them to feel peace in their bodies and their minds. I want it desperately. I’m here to try and I will try again and again but that is the reality.”

Ruben Amorim celebrated his second win over Guardiola in six weeks, and one that can provide some foundations for his rebuild of United.

“I think we did a great job, we controlled it very well,” the former Sporting Lisbon boss said.

“We didn’t allow much, of course we don’t create so much either but it was a divided game. But we believed a lot.

“It was different from Arsenal, we controlled the Arsenal game in the first half but I didn’t feel that belief. Today I felt it and I think that was the key point to change the game.

“I think for the fans it has a deep meaning especially in this context, this moment, but we had a difficult moment one week ago against Nottingham (Forest) at home, in the storm.

“After this match we are more happy, three points, but we have to continue and don’t stop. Next week we are playing again and it will change the way we see the team. Today is a good day, let’s enjoy it for 10 minutes and then think about the next game.”