Arsenal, who started the match five points behind Chelsea ahead of their trip to Stamford Bridge next weekend, began well and Andrey Arshavin created a couple of half chances.
But United, who looked dangerous every time they attacked, got the breakthrough they were after when Nani left three Arsenal defenders for dead, chipped in a cross that Arsenal goalkeeper Manuel Almunia could only push it inside his far post.
Four minutes later and United were 2-0 ahead. Reminiscent of Ronaldo’s goal in the Champions League semi-final against Arsenal last season, Rooney a United break juts outside his own penalty box when he found Nani. Rooney then ran 60 yards to meet Nani’s pass and sweep home his 22nd goal of the season.
Any chance Arsenal had of getting into the game vanished in the 52nd minute when they once again carved Arsenal open on the counter-attack, this time it was Park Ji-Sung beating Almunia from just inside the box.
Arsenal did pull a goal back with 11 minutes to go when Thomas Vermaelen’s volley took a deflection off Jonny Evans. But that was a mere consolation goal. Arsenal’s youngsters were once again found wanting in a big game.