Robin van Persie curled in an injury time winner for a 3-2 Manchester United victory to thwart a resilient City comeback in another enthralling Manchester derby.
Wayne Rooney had given United a 2-0 lead at the interval lead before Ashley Young had a goal erroneously disallowed for offside. One minute later Yaya Toure hit back for the hosts and Pablo Zabaleta arrowed in an equaliser with five minutes remaining.
But Van Persie's free-kick - via a deflection from the cowardly Samir Nasri - decided the encounter, sparking hysteria in the away end behind Joe Hart's goal.
Rio Ferdinand was struck by a missile and was left bleeding during the celebrations, but played out the final two minutes as United defended their lead.
The victory ends City's unbeaten run this season and is their first defeat in the Premier League since December 2010 while United now lie 10 points clear of their rivals.