Manchester United's Wayne Rooney wary of threat posed by West Ham's Andy Carroll

Wayne Rooney has urged Manchester United to pay special attention to Andy Carroll on Wednesday night.

Having working alongside the 23-year-old during Euro 2012,Rooney knows Carroll could provide a defensive headache to his United team-mates at Old Trafford.

"Andy Carroll is a handful," said Rooney. "I am sure if you ask any defender, they find it difficult to play against someone like that who is good in the air and on the floor.

"He is physical and makes it hard for opponents. That type of player doesn't always get all the goals but they can cause trouble up front and create problems."

United are top of the Premier League despite managing just a single clean sheet and Rooney acknowledges that is a situation that will have to change.