“I watched Sunderland beat Chelsea the other night and not only are they fighting for Gus Poyet, but he has also got them playing some good football.
“They controlled large parts of the game and had some good possession. It will be a more difficult game than people will imagine.”
United booked their place in the semi-finals after a 2-0 victory over Stoke, thanks to goals from Ashley Young and Patrice Evra. But the Red Devils must beat Sunderland over 180 minutes in order to reach Wembley, where they could face Manchester City, should the Blues defeat West Ham.
A cup victory would be a needed success for David Moyes, who is still adapting to life as United boss. After losing their third round FA Cup tie at home to Swansea, the Scot will be desperate to get back to winning ways against the Black Cats.
Evans’ place in the first team could be under threat however, with club captain Nemanja Vidic set to return to the squad, after sitting out the loss to Swansea last weekend.