The absence of Robin van Persie was the first worrying sign, and United were strangely sat deep as City played around them with greater hunger and skill. When Sergio Aguero put the hosts 1-0 up at the 16-minute mark, it was no surprise, Aleksandr Kolarov's cross eluding everyone in the area for the Argentinian to volley home at the far post.
As the first half drew to a close, United hadn't laid a glove on their opponents, and it was comfortably the worst they'd played since David Moyes took charge. Yet things were about to get a lot worse. A second half open with many possibilities was made a lot more difficult just before the half-time whistle when a corner allowed Yaya Toure to deflect the ball into the net at the far post.
United needed to find some drive from somewhere, but there were no changes at half-time, and the second period soon turned into a catastrophe. Fine play from Kolarov and Alvaro Negredo allowed City to maneouvre around a completely absent United backline to find Aguero to volley in a second.
The Red backline were now completely AWOL as both managers lost control of the game - it proved to be a lot better for City, who were all over United, and Samir Nasri, of all people, added a fourth after taking advantage of a United defence that looked beyond awful - they looked like they couldn't be bothered.
Most worrying of all, the response from United and Moyes was to introduce Tom Cleverley, although shoring up the midfield did seem to stem the flow of City attacks (although probably more down to City taking their foot off the pedal.) City didn't go close again until Edin Dzeko's fierce drive, from a counter-attack that was chillingly reminiscent of the 6-1, blasted straight at David de Gea, who spilled the ball but managed to pounce on it before it could roll over the line.
United made a late charge to salvage some pride, and Patrice Evra struck the post from a corner before a brief goalmouth scramble saw City eventually clear their lines. Wayne Rooney, however, stepped up to pull a consolation goal back shortly afterwards, blasting in an excellent free-kick to put United above Swansea City at least.