Ryan Giggs's stint as Manchester United manager got off to a winning start this evening as Wayne Rooney and Juan Mata both scored braces in a 4-0 victory over ailing Norwich City at Old Trafford in the Premier League.

Norwich thought that they might have sneaked in front inside the first 10 minutes, but Jonny Howson's goal from close range was ruled out because Ricky van Wolfswinkel had pushed Phil Jones at the back post to head across to his teammate.

United had little bite in the first half, with Danny Welbeck and Antonio Valencia testing John Ruddy from narrow angles before they made the breakthrough five minutes before half time.

It came from the penalty spot and Rooney after a cross escaped three Norwich defenders to reach Welbeck, who was tripped up by Steven Whittaker.

Rooney doubled the hosts' lead inside the first two minutes of the second half by curling a low 20-yard shot in off the post after Norwich's players had given him plenty of space in a central position.

Norwich almost halved the deficit just before the hour mark, but Robert Snodgrass's free kick wasn't close enough to the corner to really test David de Gea.

Minutes later it was three when Mata, who was left on the bench by interim manager Giggs, volleyed home from close range just moments after coming on.

The Spaniard made it four in the 72nd minute by nodding home Valencia's mishit shot from a couple of yards.

Substitute Javier Hernandez had a clear-cut chance to make it five in injury time but scuffed his shot wide of the target.

Three points mean that United remain in seventh and six points behind Tottenham Hotspur in sixth.

For Norwich, they're still outside the bottom three by a point despite their fourth loss in a row.