(CNN) -- Robin van Persie scored against his old club to give Manchester United a precious 1-0 win over Arsenal at Old Trafford on Sunday.
A tight but scrappy game was decided in the 27th minute when the Dutch striker rose to meet Wayne Rooney's corner which looped over a helpless Wojciech Szczesny in the Arsenal goal.
The result moves David Moyes' team up to fifth with 20 points, five points behind Arsenal who still top the league despite the loss.
"It was a good result for us today. Arsenal have been in terrific form this season and we had to play well today to get the result," Moyes said.
"I thought we started the game well -- we were very good in the opening 20-30 minutes of the game -- and I thought in the end our determination, our effort, our commitment helped us in the second half when we were under more pressure."
The only downside for United was a head injury to defender Nemanja Vidic who was forced to retire moments before halftime when he and keeper David de Gea clattered into one another. The former Serbian international has been taken to hospital for further treatment and tests.
While the result created joy on the red side of Manchester, the other half could not have been more blue after Manuel Pellegrini's City slumped to a 1-0 to second-from-bottom Sunderland.
Phil Bardsley's 21st minute goal proved the difference between the two sides and continued the steady progress made at the Stadium of Light since Gus Poyet took over from Paulo di Canio who was sacked in September.
The Uruguayan has steered the Northeast side to three wins in five games in all competitions since taking over.
But despite collecting six points from their last three league games, Sunderland remain in 19th place.
Manchester City have now lost four times in the league this term. This latest setback sees them slip to eighth in the table with a return of 19 points from 11 games.
Tottenham Hotspur could have risen to third in the table on Sunday, but instead Andre Villas Boas' side are seventh following a shock 1-0 defeat to Newcastle United at White Hart Lane.
Loic Remy scored the only goal of the game in 13th minute, guiding the ball home after receiving a pass from Yoan Gouffran.
Newcastle keeper Tim Krul made a series of outstanding saves to deny Spurs and secure three points for the Magpies lifting them to ninth in the table.
In Sunday's remaining Premier League fixture, Swansea City and drew with Stoke City 3-3.