Sir Alex Ferguson, the Manchester United manager, expressed confidence upon arrival in Italy yesterday that this evening's Champions League quarter-final, first leg at the Olympic Stadium will pass peacefully, with no repeat of the ugly scenes that accompanied the same fixture 12 months ago, but Daniele De Rossi, the AS Roma midfield player, gave warning that there can be no such guarantees as he issued a plea to his club's fans.

“It's important to appeal to our fans because we know that there were big problems last time,” De Rossi said. “But we can't control everything, for example things can happen 15km from the stadium. It's not easy to say to somebody who carries a knife that they should change their ways. But I say this to our supporters: 'We give you a very good team, so please give us a stadium with emotion and feeling but no violence.' ”

When United visited Rome at the same stage of last season's competition, three of their fans were stabbed on the way to the ground and a further 18 injured either in separate incidents in the city or in clashes with riot police in the stadium.

The Italian club have been warned by officials from Uefa, European football's governing body, that violence could jeopardise their hosting of next season's Champions League final.