Sir Alex Ferguson admits he is concerned about the prospect of crowd trouble when Manchester United face Roma in tonight’s Champions League quarter-final.
Police in Rome have mounted a major security operation ahead of the game after violence during previous meetings between the two.
“After the experience of last year it is a concern,” Ferguson said.
“But I think the police have been working hard to ensure it doesn’t happen again.
“For the reputation of both our teams we hope it is a good game, a competitive game.
“There is rivalry among the fans, there is nothing wrong with that, but as long as it stays the rivalry of supporting your own team then we can go home happy in the knowledge that everything has gone peacefully.”
Twelve United fans were stabbed when they visited Rome for last season’s quarter-final, and dozens of others were injured inside the stadium when they were baton-charged by police. Another five supporters were stabbed when United returned to Rome in December.
Uefa has warned it may take next year’s final away from Rome if there is a repeat of those scenes.
A Uefa spokesman said: “There has been great progress made inside Rome’s Olympic Stadium but the attacks one kilometre from the stadium worry us.
“The police say they cannot control the city and that is not satisfactory. If we see a repeat of what we have seen so far it may be wise to move the 2009 Champions League final from Rome.
“Knifings are attempted murder. We cannot be held hostage by a few criminals.
“Apart from Manchester’s fans, Real Madrid supporters were also stabbed here in February and their buses were stoned, even after they had been kept back in the stadium two hours after the game.”
Roma’s coach, Luciano Spalletti, said he was confident the club’s supporters would stay out of trouble.
“I have a lot of faith in our fans, who have come to understand the danger of bad behaviour,” he said.
However, the midfielder Daniele De Rossi admitted being concerned.
“It’s not easy to say to someone who wants to carry a knife that they should change their ways and stop,” he said. “I just say this to our supporters: ‘We give you a good football team so give us a stadium with emotion and feelings but, please, no violence.'”
About 4,000 United fans will be in Rome and the club have written to ticket-holders warning them of areas to avoid.