MANCHESTER, England - Manchester United ended two years of hurt on derby day by dismantling Manchester City in a 4-2 win in the Premier League on Sunday, underlining the reversal in fortunes of the local rivals this season.

City had won four straight Manchester derbies since April 2013 but the "noisy neighbours" — as former United manager Alex Ferguson once called them — were silenced in another sign of United's resurgence under Louis van Gaal.

United's sixth straight league win came despite City, the soon-to-be-deposed champions, going ahead through Sergio Aguero's eighth-minute opener.

Ashley Young and Marouane Fellaini scored to put United ahead at halftime, before more poor defending by City was punished by goals from Juan Mata and Chris Smalling in a seven-minute span midway through the second half.

Aguero grabbed a late consolation for City but it couldn't stop a sixth defeat in eight matches, a staggering decline that has left City manager Manuel Pellegrini fighting for his job.

City has slumped to fourth place, four points behind United and 12 adrift of leader Chelsea in a brittle title defence. The champions were tied on points with Chelsea on Jan. 1.

"We are not in a good moment," said Pellegrini, who rebuffed questions about his future. "We have a bad 2015 and a very bad week."

City has inflicted some painful defeats on United since its rise as a force in the English game over the last few years, notably last season when it won 4-1 at home and 3-0 away on the way to a second title in three years.

The hurt will have subsided with this win, and the swagger is back at Old Trafford under Van Gaal.

"(The fans) can go on the streets with their hats up and say, 'This year, we are the better team,'" said the Dutch coach, who was careful to play down talk of a permanent power shift in the city.

For the moment, though, the teams are heading in opposite directions.

City's heads dropped after going behind and its defence was a mess at times, particularly after captain Vincent Kompany was substituted at halftime with a groin injury.

After a bright start, capped by Aguero's tap-in from David Silva's cross to end the striker's six-game run without a goal, City struggled to match United's energy and drive.

United equalized on its first attack and never looked back, with the tall Fellaini a constant menace alongside Wayne Rooney in attack and the rejuvenated Young providing a regular supply of crosses from the left.

Young equalized from close range in the 14th after Gael Clichy's sliding tackle deflected off winger and landed in his path. He then turned provider in the 27th, sending a curling cross over the head of Clichy for Fellaini to plant a header beyond the outstretched left hand of goalkeeper Joe Hart.

"He was fantastic," Van Gaal said of Young. "He was our best player,"

The second half was even but United had a cutting edge and seized the initiative with two quick goals.

Rooney held the ball up well and fed Mata, who ran through unchallenged to place a finish between Hart's legs in the 67th. City's defending was poor for the fourth goal, too, as Young whipped in a free kick that an unmarked Smalling headed in from eight meters.

Aguero's shot from Pablo Zabaleta's cross was fumbled into the net off the post by United goalkeeper David de Gea, but there was to be no record fifth straight derby win for City.