For those supporters still nursing the scars of that terrifying ordeal in the Italian capital, revenge was indeed sweet. Retribution, as was fit and proper, came in the form of a sound beating, and not the sort dished out by baton-wielding police.

Three goals inside the first 20 minutes, four in the opening half, six within the hour, sent United into the semi-finals of the Champions League for the first time in five seasons. Never before have United overcome a first leg deficit to progress into the next round of the knock-out stage. As for scoring seven goals, their previous best was five.

If Old Trafford has enjoyed a more satisfying evening in Europe, an ecstatic gathering, including Sir Alex Ferguson, did not let on. Fears that United's resolve was starting to waver after defeats at home and abroad, compounded by a team sheet, missing many influential figures, were allayed in the most spectacular fashion.

"The best in my time here," conceded Ferguson, after witnessing one of the most emphatic wins in Champions League history. "It was a fantastic performance, there's no other description. The key was confidence. We believed in ourselves. We have had a couple of bad results in the last week but all great teams get over those mishaps. Recovery is the most important thing and we recovered tonight."

Luciano Spalletti's Roma, who flew into town boasting a 2-1 first leg advantage, hardly knew what had hit them. From the first whistle to the last in that dramatic opening period, United looked and played like a team possessed. If the chief sorcerer was Cristiano Ronaldo, the Portuguese was blessed with an abundance of willing and able apprentices.

Six days ago, Ferguson had accused the German referee, Herbert Fandel, of being Roma's 12th man. Last night, United's supporters provided the extra body, unsettling the visitors with the hostility of their welcome and then roaring their approval as Alan Smith set the tone with a rasping tackle.

Yet not even the most optimistic supporter could have imagined such an outcome. Without Paul Scholes, suspended after seeing red in Rome, and the injured Nemanja Vidic, Gary Neville and Luis Saha, there was ample reason to fear an accomplished Roma side, happy playing on the counter-attack as previous victims Lyon will testify.

Oh, how Ferguson will delight in the plaudits heading his way this morning. In 1999, United's understudies stepped up to the mark as the club, hampered with injuries and suspensions, chased down an unprecedented treble.

Last night, Smith's debut goal in Europe was as warmly received as Ronaldo's brace, while the performances of Darren Fletcher, John O'Shea and Gabriel Heinze would suggest history could yet repeat itself.

It has been 23 years since AS Roma last made any real impression in Europe and then it all ended in tears, in their own back yard, confounded by Bruce Grobbelaar's wobbly legs in the 1984 final against Liverpool. Last night it was the turn of the Roma goalkeeper Doni to cringe with embarrassment.

United's slick, fast and penetrating passes had already unnerved the visitors by the time Michael Carrick opened the account, a terrific strike from outside the box, taken early, thwarting Doni in the 12th minute.

On the touchline, Spalletti jumped to his feet, gesticulating wildly. Roma's response was not what he had in mind. They simply capitulated.

Caught cold, yet again, by the devils in red, spreading the ball with ease and precision, Heinze and Ryan Giggs combined to help Smith break his duck. His first goal for United in Europe, it also marked his return from long-term injury. Not since November of last season has Smith, who broke his leg, been on the United score sheet.

But the jubilation did not stop there. The majestic procession continued, with Rooney adding a third in the 18th minute, another perfectly crafted effort, instigated by Giggs and turned in by the United No.8. It was Rooney's goal, when United were down to 10 men, that had given the side hope in Rome. Last night, his show of character was amply rewarded.

Ferguson promised his players that Francesco Totti would feature in last night's return leg. And sure enough, rumours of Roma's 30-year old captain struggling with a thigh or back problem proved unfounded. The striker didn't get a look-in and in the aftermatch of this mauling, will wish he had feigned injury.

Leading candidate for the PFA Player of the Season and the world's best according to Ferguson, Ronaldo is not short of admirers. Last night, though, he finally cracked Europe. Not only did he score his first and second goals in the competition, he ran the show. It was the perfect master-class.

From the dazzling run that left Roma's defenders leaden-footed and bewildered and their keeper exposed two minutes before half-time, to the simple, assured touch that made it 5-0 moments after the restart, Ronaldo was quite exceptional.

The composed Carrick, with another breathtaking effort from distance, made it six on the hour and although Roma, through Daniele De Rossi, pulled a goal back, the full-back, Patrice Evra, maintained United's advantage with their seventh in the 81st minute.

Manchester United Van der Sar, Brown, Ferdinand, Heinze, O'Shea (Evra 52), Ronaldo, Fletcher, Carrick (Richardson 73), Giggs (Solskjaer 61), Rooney, Smith. Subs: Kuszczak, Dong, Cathcart, Eagles Booked Smith, Ferdinand Roma Doni, Panucci, Mexes, Chivu, Cassetti, Wilhelmsson (Rosi 88), De Rossi (Faty 86), Vucinic, Pizarro, Mancini (Okaka Chuka 90), Totti. Subs: Curci, Defendi, Ferrari, Taddei Booked Cassetti, Mexes Referee L Michel (Slovakia)