Vidic believes that in many respects tonight will be a tougher assignment than the one in Madrid.
He said: "This will be a more difficult game. We are playing at home and are defending a positive result.
"But it is also a dangerous result because they have the ability to hurt with a free-kick or from set-pieces.
"They are so good on counter-attacks but when they are at home, their fans want them to attack all the time and press high. At Old Trafford, though, they will be more relaxed and more dangerous."