Man Utd 3-1 Man City
Paul Scholes made up for lost time with a pair of headed goals to sink City in the 129th Manchester derby - and send United top of the table.
Scholes, who had not started a Premiership game since 4 October because of a groin injury, bookended United's win with two clinical finishes from clinical crosses.
Ruud van Nistelrooy's 12th Premiership goal of the season completed United's 50th Old Trafford win over their city rivals - and for a while it seemed that few of the previous 49 could have been more comfortable.
But Shaun Wright-Phillips' 52nd-minute goal ended a seven-hour goal drought for Kevin Keegan's side and simultaneously heralded a renewed effort from the visitors.
City had chances to peg their rivals back, but the champions were nevertheless well worth their win.
OLD TRAFFORD GOALS
7 mins: Scholes flicks home from Gary Neville cross
34 mins: Giggs cross headed home by Van Nistelrooy
52 mins: Wright-Phillips pulls one back for City
73 mins: Scholes heads home his second to seal victory
The home side were in control from the start, Scholes celebrating his Premiership return with the opening goal inside seven minutes.
A patient build-up saw United pick and probe before Gary Neville swung in an inviting cross for Scholes to flick a head at and send the ball beyond the reach of David Seaman.
Ryan Giggs should have made it two on 18 minutes, but blazed wide when left in space from Van Nistelrooy's lay-off.
But United's first-half dominance was underlined by Van Nistelrooy's header on 34 minutes.
City centre back Richard Dunne missed a routine ball in the middle of the pitch and was then out of position as United's Dutch striker cleverly headed home Giggs' resulting cross.
City were restricted to a deflected Robbie Fowler shot from distance, which forced Tim Howard to scramble back and tip the ball over his crossbar.
Van Nistelrooy celebrates his goal
Otherwise, the American keeper was largely underemployed until Wright-Phillips grabbed City a lifeline.
The goal came out of nothing as the wing-back jinked past Scholes and then eased past static defending from Phil Neville and John O'Shea before screwing an angled shot across Howard and into the far corner.
His bolt from the blue sparked life into a previously listless City and Fowler was agonisingly close to an equaliser when he got his head to an emergency clearance from Howard but watched the ball spin wide of an unguarded net.
But Scholes' second of the game 17 minutes from time made the game safe.
His close-range header was rough luck on former England keeper Seaman, who had just made the save of the match to keep City in the game.
Seaman pushed Van Nistelrooy's low shot from a Scholes pass against a post, Dunn scrambling the loose ball clear for a throw.
But, from that throw-in, the lively Kleberson swung over another inviting cross for the resurgent Scholes to head powerfully beyond Seaman's reach.
Nicolas Anelka and Steve McManaman were both denied by an alert Howard as City searched for a late lifeline, but by then the derby had been won.
Man Utd: Howard, Gary Neville, Ferdinand, Silvestre, O'Shea, Kleberson (Ronaldo 74), Phil Neville, Keane, Giggs, Scholes, Van Nistelrooy.
Subs not used: Carroll, Butt, Forlan, Fortune.
Man City: Seaman, Jihai, Dunne, Sommeil, Distin,
Wright-Phillips, McManaman, Barton, Sinclair (Wanchope 81),
Subs Not Used: Stuhr-Ellegaard, Reyna, Sibierski, Berkovic.
Booked: Barton, Jihai.
Referee: M Halsey (Lancashire).