Ottmar Hitzfeld is convinced Schalke can upset Champions League opponents Manchester United.
Hitzfeld, who beat United with Borussia Dortmund and Bayern Munich on his way to two Champions League crowns, believes his old rival could be in for another surprise.
"Ferguson knows how difficult this task is," said Hitzfeld.
"The danger is his players think subconsciously, "Raul plays for Schalke but who else have they got?" United are favourites, but in a semi-final there is always a 50-50 chance. Schalke can also create a fairy-tale."
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