Having slipped well off the pace in the league in recent weeks, the Catalans now host United on Wednesday in the first leg of the last-four tie and Cruyff warns they cannot make mistakes.

"Barcelona will have to do things well. If there aren't any stupidities, the tie is there to be won," said Cruyff, who achieved legendary status after hugely successful spells as a player and a coach at the Nou Camp.

Frank Rijkaard's side have not won any of their last four league games and are now 11 points adrift of arch rivals Real Madrid in the race for the title.

However, Cruyff hopes the Catalans can rediscover their best form in Europe.

"If Barcelona play like they know how, they have a chance of getting to Moscow (for the Champions League final next month).

"Even though they are stumbling in the league and have literally thrown away the title, my thoughts don't change. Europe is another story, another competition. There is a different mentality and I believe it will be an even tie."