"It's not impossible to stop Rooney, a lot of teams have done it.
"He's a world class player and if he's not scoring goals he can be hurting you in other ways.
"But they've got so many options going forward you can't pinpoint one player to try to stop because, if you do, there's another angle.
"There's (Ryan) Giggs and (Cristiano) Ronaldo, and (Louis) Saha has been absolutely on fire this year.
"And, at the heart of it, you've got Paul Scholes pulling the strings.
"Scholes is world class. He was one of the best attacking midfield players in the world two or three years ago and he is still one of the best in the game.
"He can pass, score goals and he can even play in that deeper role.
"He's just a quality player and is one of the many players we have to keep a close eye on. You can't pinpoint one.
"United have been on fire since the start of the season.
"I saw them playing in a few games and some of the football they were playing was outstanding.
"I haven't seen a lot of them recently to be honest but their results and the fact they're sitting at the top of the league backs me up on that."