Manchester United broke their losing run against Manchester City in convincing style with a 4-2 victory over their rivals at Old Trafford.
City were bidding for a fifth successive derby win and took the lead in the eighth minute as Sergio Aguero tapped in David Silva's cross.
But United responded well, levelling in the 14th minute through Ashley Young before going ahead just before the half-hour mark when Marouane Fellaini headed home.
Juan Mata made it 3-1 midway through the second half and Chris Smalling extended the advantage further not long afterwards.
Aguero pulled a late goal back for City but it was nothing more than a consolation as United recorded their sixth consecutive Premier League win and moved four points ahead of their rivals in the table.
The goal was Aguero's 100th for City but it was United who were doing all the celebrating at the final whistle.
For City, it is their sixth defeat in their last eight matches in all competitions and puts an emphatic end to their dominance over United in recent years.
Manchester United: De Gea (5), Blind (6), Smalling (7), Jones (6), Valencia (6), Carrick (6), Fellaini (7), Herrera (7), Mata (7), Young (8), Rooney (6).
Subs: Rojo (5), Di Maria (5), Falcao (5).
Manchester City: Hart (5), Clichy (5), Demichelis (5), Kompany (4), Zabaleta (5), Fernandinho (5), Milner (5), Navas (5), Toure (5), Silva (6), Aguero (7).
Subs: Mangala (5), Lampard (5), Nasri (5).
Man of the match: Ashley Young