Louis van Gaal's dream turned into reality as Manchester United put four goals past City in a superb derby win at Old Trafford.
Sergio Aguero's early opener was cancelled out by Ashley Young's close-range effort and United went in ahead at half-time after Marouane Fellaini's powerful header.
Juan Mata added a third after the restart and Chris Smalling also found the net before Aguero pulled one back at the death to make it 4-2.
Van Gaal said before the match that he and his players had been "dreaming" of beating their arch rivals for the first time since December 2012.
But this was a victory and performance that was surely beyond the United manager's wildest expectations.
Once United had levelled the scores, they out-performed the Barclays Premier League champions in every department.
Mata rattled City with his creativity and vision, Michael Carrick ensured the hosts played at a high tempo at the base of midfield and Ander Herrera had possibly his best game in United red.
But the best players on a pitch full of mega stars were Young and Fellaini. Van Gaal played down his role in United's revival before kick-off, but the Dutchman deserves huge credit for the way he has turned these misfits into two of the most deadly players in the top flight on current form.
Pablo Zabaleta, one of the league's most experienced and consistent performers, could not handle Young's pace all afternoon and Fellaini just bullied every player he saw in blue.
The result means United remain third in the table, four points ahead of City. The Red Devils are just one point behind Arsenal and eight shy of table-toppers Chelsea.
The biggest repercussions are likely to be felt across town. City boss Manuel Pellegrini was taunted with chants of "sacked in the morning" towards the end of the match, which brought to an end a run of four successive derby wins for the Blues.
Any hopes of retaining the title are now surely over for Pellegrini and the pressure on the Chilean is continuing to mount.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article