Nemanja Vidic is determined Manchester United will not lose their focus ahead of Tuesday's battle of Britain showdown with Celtic.
Although Vidic has experienced the intensity of derby games in Moscow and his native Belgrade, the two meetings against Gordon Strachan's side in 2006 provided him with the best atmosphere he has ever known.
Vidic knows United have the class to repel the Scottish challenge. But he has warned his team-mates not to let the noise divert their attention from the need to claim a home win and said: "The champion team of Scotland will be desperate to beat the champions of England. 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."
He added: "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."
Sir Alex Ferguson is pondering a surprise decision to leave out Cristiano Ronaldo as, after consultation with former assistant and current Portugal national coach Carlos Queiroz, he believes the winger is struggling to complete two games in a week.
"Carlos feels Cristiano is still finding it hard to recover from a Saturday game to a Wednesday," said Ferguson.
"I need to look at this game and the fact it is on a Tuesday and assess whether to bring in Nani."
Definitely out is Patrice Evra, who suffered a hamstring injury against West Brom on Saturday and will not be risked, so John O'Shea will fill the left-back role.
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