It was a match that saw Carlos Tevez return to Old Trafford in the arch enemy's jersey and that was just the very start of the drama.
Wayne Rooney gave United the lead in the second minute of play, before some tireless work from Tevez to get the better of Ben Foster setup an equaliser from Gareth Barry.
Darren Fletcher restored the hosts' lead just after half-time with a well-placed header but Sir Alex Ferguson's side weren't ahead for long.
A stunner from Craig Bellamy restored parity in the Manchester derby, however, the pendulum swung back in United's favour with just 10 minutes remaining.
Fletcher was the scorer once again and the Scotsman's second of the day looked as if it would be the decisive blow.
But it was just the start of around 15 minutes of utter chaos at Old Trafford.
Bellamy made the most of a horrendous error by Rio Ferdinand to silence the Theatre of Dreams right at the end of the regulation 90.
Fortunately for Ferdinand, Michael Owen was on hand to bail him out with one of the most dramatic last-minute winners in Premier League history.
His goal in the sixth-minute of injury-time, which Mark Hughes was fuming about due to the fact that there was only supposed to be four extra minutes, sparked scenes of wild celebration among the United contingent.
Ferguson and Gary Neville went absolutely bonkers and footage of their actions in the immediate aftermath of the goal that many won't have seen before has gone viral on social media.
Check it out here...
Video: Neville & Ferguson celebrating Owen's winner v City in 2009
Now that's what you call passion.
United had made all three subs, but Neville still decided to go through a warm-up routine in the 96th-minute, just to wind up the City fans even more.
He's always loved ruffling feathers has ol' Gary.
Neville actually received a warning from the FA for his rather provocative celebration, the Sky Sports pundit defending his actions by saying at the time: "In football, we have become too sensitive. You celebrate a goal because you are winning a football match.
"Fans give you loads of stick. You give them a bit back. That is football."