Manchester City manager Manuel Pellegrini insists he is not thinking about winning the Premier League title, but for United counterpart David Moyes such a scenario remains nothing more than a pipe dream after he admitted full responsibility for their disastrous season.
The Red Devils slumped to a sixth home defeat to their 'noisy neighbours' after Edin Dzeko scored twice - including the fastest Premier League goal by a visiting team after 44 seconds - and Yaya Toure added a late third.
United have now lost more matches at home this campaign than in the last three seasons combined, and in doing so became the first reigning top-flight champion in 51 years to lose six or more of their first 15 home matches since Ipswich in 1962-63.
The result put City within three points of leaders Chelsea with two matches in hand, but Pellegrini refused to entertain talk of the title being theirs to lose.
"I don't think so. We will continue fighting with the other three teams, Arsenal, Chelsea and Liverpool, and we have to win the two postponed games and continue playing the way we play," said the Chilean.
"I am not thinking about the title. Tomorrow we are thinking about Arsenal (who they face on Saturday)."
By contrast, Moyes was left to defend another poor performance from his side which left them 12 points adrift of fourth, with Chelsea a distant 18 ahead.
"I take responsibility for the team, I always will do," said the Scot, whose side have taken just seven points from 13 games against the present top nine and scored only one goal - and that from a corner.
"Everyone knows this is going to be a job which is going to take a little bit of time to get the way we would like it, but that is the job and I recognise that.
"I thought it would be a tough year for us, no doubt about that, but I hoped it would be much more competitive and closer to the top of the league than we are at the present time."
Moyes has consistently shouldered the blame and deflected criticism away from his players and he did so again, although even he admitted he did not understand why they were not up for the game against their rivals from the off.
"We never started well. We never gave ourselves a great opportunity to get into the game," added the Scot.
"Manchester City started really fast and conceding a goal after 30-40 seconds made it difficult.
"I just think we never came out of the blocks. You prepare the players, you warm them up, you do all the things to have them ready, but we just never started.
"It gave them (City) a real big lift to get a goal so early on.
"We had to try to make sure we got through that 10-15 minute period when they were out of the blocks.
"After that we weathered it and got ourselves back into the game and finished the half quite strong.
"The key to it was not to concede a second goal so we could always give ourselves a chance back in there, but I didn't think we started the second half well.
"We brought pressure on us by our play and in the end we conceded a corner just before that and there was another one and then that led to a goal.
"It was obviously poor marking and we should have done much better."
In a relatively incident-free Manchester derby, the only controversial incident came in the first half when United midfielder Marouane Fellaini escaped with a yellow card after appearing to catch Pablo Zabaleta in the face with an elbow.
Pellegrini said he saw it but accepted referee Michael Oliver's judgement. Moyes said he initially did not think it was a foul and had to be told afterwards it was a potential red card.
"I didn't see the incident. If the referee decided not to send him off I respect that," said the City boss.
Moyes added: "I genuinely have not seen it again. When I first saw it in the game I didn't even think it was a free-kick so I couldn't even tell you, but by what I am hearing people are saying it could have been worse."