Roberto Mancini knows Manchester City must repeat their FA Cup semi-final performance against United if they are to end their trophy drought.
Yaya Toure fired City into their first final since 1981, where they will play the winners of Sunday's clash between Bolton and Stoke.
Mancini's men will be favourites to claim their first trophy since the 1976 League Cup at Wembley next month but the Italian reckons the final will be even tougher than the semi.
He said "I'm very happy. I'm very happy for our supporters.
"They deserve to have a day like this afternoon.
"We mustn't forget we play another game.
"Today, we won only the semi-final."
City's travelling fans must have been fearing the worst after an opening quarter dominated by United which saw Dimitar Berbatov produce two glaring misses.
Mancini added: "It's difficult to play against United.
"They're used to playing this (type of) game every year. For us, it was the first time after a long time.
"Maybe we had some fear in the first 20-25 minutes.
"In the last 10, 15 minutes of the first half, we started to play high, we started to press.
"In the second half, we dominated the game.
"I am happy because we had fantastic spirit and we beat a team like Man United."
It would not be a Manchester derby without controversy and both sides duly delivered as Paul Scholes was sent off for a thigh-high tackle on Pablo Zabaleta and Mario Balotelli was involved in some ugly exchanges with United players on the final whistle after celebrating in front of opposition supporters.
Mancini said of the latter incident: "I didn't see it. I want to wait because every time, 'It's Balotelli's fault'."
When the incident was describe to him, Mancini joked: "We can put him in jail? Next week, we can put him in jail for this."
Toure was named man of the match for what was a marauding performance but Mancini refused to single him out.
"Yaya is a fantastic player," he said.
"But I think today in the second half all the players played a fantastic game."
City are also chasing fourth place in the Barclays Premier League and, asked if the cup was now more important, he said: "We want both.
"I think that also we deserve to play in the Champions League because we were for one year between first and fourth spot.
"We have everything in our hands.
"If we have the same spirit we had today, we have the fourth spot."
Victory eased the pressure on Mancini to bring success to City, with the club having spent millions in pursuit of glory since the takeover of Sheik Mansour.
But he said: "I don't have pressure.
"When I decided 11 years ago to start this career, I knew that it was difficult to do this job.
"If you win, you are the best. If you lose, you are the worst manager.
"I would like to win this cup for the club, for the supporters, all the people that work at Manchester City."
Defending City's spending spree over the last two and a half years, he added: "In the past, United spent or not? "Chelsea spent or not? Arsenal spent or not?
"Manchester City was a small team until three, four, five years ago.
"I have never seen in my life a team that doesn't have good players win some titles - never."
Mancini reiterated his belief that landing the FA Cup could inspire City to win the Premier League next season.
"I believe in what I said because, for us, it's important to start to win the first trophies."
United boss Sir Alex Ferguson blamed the end of his side's treble dream on the slack defending which led to Toure's goal and Berbatov's glaring misses.
"The first 15 minutes after half-time cost us the game," Ferguson said.
"Slack moments. Edwin (van der Sar) had a bad kick out and Michael Carrick couldn't hold it and it was a goal.
"From then on, they were defending apart from a couple of counter-attacks. It's disappointing as we should've been ahead in the first half as we were the better team.
"The chances that Dimitar missed - there was a great save by the keeper but the second chance, from under the bar, if he'd have scored there, I had a feeling whoever scored first would win the match."
Ferguson challenged his players, who had won their previous seven matches, to bounce back in Tuesday night's Premier League game at Newcastle.
"It's a major game on Tuesday up at Newcastle," he told MUTV. "We're getting recovered to get ready for the game on Tuesday.
"It doesn't matter when you play, you know you've got to recover and get on a winning streak again."
