Manchester United beat Arsenal 1-0 on at Old Trafford to leapfrog their opponents and go top of the English Premier League. Ji-Sung Park's first-half goal proved to be enough for all three points for a United side that could even afford for Wayne Rooney to miss a penalty.
United, who remain unbeaten and still have a game in hand, are now two points clear of both Arsenal and Manchester City.
"We had to play well, in these major games you want to perform and I think we did tonight, particularly in the first half we did very, very well, United manager Sir Alex Ferguson said.
But the manager admitted that he had been concerned when Rooney fired his penalty way over the crossbar.
"It was an unusual penalty, normally Wayne always keeps them down, I have never known him to hit one over," he said.
"That gave Arsenal a bit of impetus but we defended very well, the back four were fantastic tonight, absolutely magnificent."
United left Dimitar Berbatov out of their starting line-up, while Arsenal gave a debut to young Poland goalkeeper Wojciech Szczesny, who saved well on a number of occasions.
Szczesny did well to stop Anderson from opening the scoring, but United were dominant in possession as Arsenal, with Csec Fabregas, Robin van Persie and Theo Walcott on the bench, could not get a handle on the game.
It looked as if Arsenal would survive to half-time, but Park had other ideas, and his brilliant reaction header put United ahead after the ball had deflected off Gael Clichy on its way to him.
Arsene Wenger brought on Van Persie and Fabregas early in the second half, but United should have had a second goal when Clichy was adjudged to have handled the ball inside the area.
Television replays suggested that the decision was harsh, but Rooney spared Arsenal by blasting the ball over the bar.
Arsenal huffed and puffed in search of an equaliser but failed to create enough chances, and United held on for all three points.
Arsenal manager Arsene Wenger said the state of the Old Trafford pitch had not helped his side's chances.
"The game was very intense, both teams were well-organised, the intensity of the game was very high and on a very bad pitch," he said.
"Overall the technical quality of the game suffered from a very bad pitch and that was why on both sides you have seen unusual technical mistakes. I don't think we failed to deliver, we lost a game and that can happen here."