Manchester United defender Nemanja Vidic says they must take out the crowd factor against Celtic tonight.

"The champion team of Scotland will be desperate to beat the champions of England," he said. "The atmospheres I experienced two years ago were the best I have known in my career and there will be more tension in the ground.

"But it is not good for the players to be too passionate. We need to be focused.

"If we put too much aggression into it or pay too much attention to the crowd, we could find it difficult. We need to stay calm and concentrate."