Sir Alex Ferguson headed back from Italy in high spirits after Manchester United’s outstanding 2-0 Champions League quarter-final, first-leg victory over AS Roma at the Olympic Stadium last night, his joy tempered only by an injury to Nemanja Vidic that will be assessed this morning. Cristiano Ronaldo and Wayne Rooney scored United’s goals, putting them on course for a semi-final showdown with Barcelona, after Vidic twisted his left knee when falling awkwardly in the first half.

The Serbia defender joined his team-mates on the flight home in the early hours of this morning but he will be sent for a scan today, with the club’s medical staff concerned that he may have damaged ligaments. “We hope it’s a nerve injury and I pray it’s not serious because he is such a vital part of our team,” Ferguson said.

Even without Vidic, Ferguson’s team stood firm for the final hour as they underlined their status as favourites to lift the European Cup. Their record away from home in Europe had been questioned, not least by Daniele De Rossi, the Roma midfield player, but a disciplined performance rounded off by goals from their young superstars earned them their first victory on Italian or Spanish soil since February 2003.

Ronaldo’s remaining detractors were surely silenced by his 36th goal of a remarkable season, a brave header six minutes before half-time. Ronaldo had been subjected to some strong challenges, Christian Panucci catching him with a stray elbow in the first half, but once again he enjoyed the last word, putting United ahead when he rose to head home from Paul Scholes’s cross. Rooney scored from close range midway through the second half to give his team what is surely an unassailable lead for the second leg at Old Trafford next Wednesday.

“I think it’s an absolutely outstanding result for us,” Ferguson said. “We showed great discipline and composure on the ball. I don’t think Roma showed any real threat in the first half.

“Ronaldo’s goal changed the game. It was a fantastic header. After that we rode our luck for a period at the start of the second half, but I thought we deserved our win. It’s a fantastic result, but in football you can never take anything for granted.”

It was a “good header” and a “very good performance”, according to Ronaldo. He believes that United have a great chance of winning the tournament. “The team is playing fantastically,” he said. “It is more mature. The Champions League is different from the league. Manchester United want to win it this season.”

Equally satisfying was that last night’s game passed peacefully. There were some missiles thrown between the rival supporters, but, with a heavy police presence inside and outside the stadium, there was no repeat of the ugly scenes that accompanied the clubs’ meetings last season.

Barcelona lie in wait for United in the last four, Bojan Krkic, their outstanding 17-year-old forward, scoring in a 1-0 win away to Schalke 04. That would mean United returning to the Nou Camp, the scene of their dramatic victory over Bayern Munich in the 1999 final, but Ferguson will not allow his players to look beyond their Barclays Premier League match away to Middlesbrough on Sunday as they continue their quest for glory on the domestic and European fronts.