Less than 60 seconds had passed when Cristiano Ronaldo, a blur of red and white on the left flank, tore past the Benfica fullback Nelson. His driven cross would come to nothing - nobody in the Manchester United side could keep up - but Ronaldo had signalled his intention to leave a mark on this match.

Only 24 hours earlier he had claimed he was unconcerned about the criticism that followed allegations of diving at the weekend. This was a performance designed to strike back.

There was no goal to embellish the display but a wonderful cross 16 minutes into the second half that allowed Ryan Giggs to head in unchallenged at the far post secured United's passage into the last 16. It was a moment indicative of Ronaldo's contribution, the mercurial winger with his mesmerising trickery and fleet-footed step-overs troubling the team he had supported as a boy.

That dexterity sat uncomfortably alongside the furore that followed the penalty awarded at Middlesbrough on Saturday.

Alex Ferguson had launched a robust defence of Ronaldo, dismissing Gareth Southgate, the Middlesbrough manager, as "naive" after he had dared to suggest the United winger had cheated. Ferguson's view was at odds with the official match report in the United programme which described how "the Portuguese winger went down under (Mark) Schwarzer's challenge but television replays showed there to be minimal contact, if any".

Ronaldo's penchant for tumbling is well known back home. It is a trait that followed him from Sporting Lisbon to United three years ago and it is one he has still to shed. Indeed Benfica's defender Luisao neatly summed up the 21-year-old: "In Portugal everyone knows how Cristiano Ronaldo plays. He is a genius on the ball but on many occasions he abuses this quality through his faults."

There had been no sign of Ronaldo's darker side here, though, only flashes of occasional brilliance, with a 30-yard free-kick that forced Quim to back-pedal frantically before tipping over on the half-hour mark. The Benfica goalkeeper had to be at his best to keep out another Ronaldo shot on the stroke of half-time, the midfielder picking up possession on the left before swerving a drive from just inside the penalty area toward the top corner.

The alacrity with which Ronaldo was taking his chances suggested, though, he was too eager to impress. An opening on the edge of the area in the 44th minute would normally have been converted but he got the ball stuck between his feet, and the shot was tame and easily saved.

The same could not be said for Nelson's goal, the Benfica fullback sweeping a wonderful 25-yard shot beyond Edwin van der Sar to give the visitors a lead that was cancelled out with virtually the last action of the first half when Nemanja Vidic headed home Giggs's free-kick.

Ronaldo would later deliver a similar ball to Giggs that the Welshman dispatched. The Portuguese celebrated quietly on the far side of the stadium; his impressive display had already raised the decibels in this special arena.