SUNDERLAND did not have much of an answer to a rampant display from Manchester United in the first hour at Old Trafford, but Sir Alex Ferguson has backed the Black Cats to survive a threat of relegation.

Despite a spirited finale from Sunderland, the Red Devils could have been more than three goals up before Fraizer Campbell did pull one back 18 minutes from time.

While Manchester United remain six points clear of rivals Manchester City at the top of the Premier League, Sunderland’s woes continue and head to Southampton on Saturday sitting just a point above the bottom three.

But Ferguson said: “They deserved a goal as they worked so hard, they had injuries in the second half and it was a young team that kept going. I don’t think they will have any problems, they seem a reasonable team.”

The United boss, however, was more impressed by his own team’s display, which highlighted their intention to wrestle the Premier League crown back to Old Trafford.

Goals from Robin van Persie, Tom Cleverley and Wayne Rooney secured the points – and there could have more.

“I don’t know whether my players relaxed at 3-0 or Sunderland got a grip of the game, but up to then some of our play was fantastic and we could have scored a lot of goals, possibly some of the best of the season, some of it was very good,” he said.

“Tom Cleverley’s goal was a marvellous piece of interchanging play with a one-touch finish, a really superb goal and that epitomised the way we were playing at that moment. I have no complaints about that first hour, it was wonderful to watch.”

But the show was stolen by van Persie and Rooney. The pair have conjured up 44 goals and 18 assists between the m in 2012, which illustrates why Ferguson was so keen to combine them together in a red shirt.

Van Persie took his tally to 15 goals for the season, with Rooney’s tap-in ensuring the duo have scored nine goals between them in the last four matches to extend United’s unbeaten run to 11 matches.

And Ferguson reckons more could come. He said: “Sometimes they still don’t pick out Robin van Persie’s runs as well as they should but his movement always kept them on the back foot and Wayne could have scored four in this game easily – he hit the bar and missed two or three in the first half. But he has a goal and that is important, it keeps his run going.”