Barcelona, April 24:

A rare failure of nerve by Cristiano Ronaldo cost Manchester United the chance of a famous victory but Sir Alex Ferguson’s side still emerged as favourites to reach the Champions League final after a goalless draw with Barcelona in their semi-final first leg match here on Tuesday.

It could have been so much better for the English champions if Ronaldo had not missed a third minute penalty but, after an enthralling contest that Barcelona undoubtedly edged on points, United will not complain too loudly about the outcome.

The visitors’ display never threatened to scale the heights they have touched at times this season and have resulted in Ronaldo, Wayne Rooney and company being hailed as the richest collection of talents ever assembled by the club by both their manager and Sir Bobby Charlton.

But a gritty defensive display and the relatively meagre ration of real chances they accorded Barcelona will have given Ferguson justifiable cause for optimism about the outcome of next Tuesday’s second leg.

Deprived by the services of centreback Nemanja Vidic, Ferguson must have thought his luck had turned for the better when Ronaldo headed Rooney’s corner against the arm of Gabriel Milito just 90 seconds into the match. The defender, drafted in to replace Barca’s suspended captain Carles Puyol, could do little to get out of the way but the fact that his arm was raised ensured Swiss referee Massimo Busacca had no hesitation in pointing to the spot.

Against the background of a cacophony of Catalan catcalls, Ronaldo’s customary pre-penalty gunslinger stance appeared as confident as ever. The strike that followed carried the ball a foot wide of Victor Valdes’s left-hand post.

Barcelona immediately set about making the most of their let-off and United lived dangerously for a while as Lionel Messi repeatedly jinked and swerved his way into dangerous positions.

United might easily have been awarded a second penalty just before the half-hour when Ronaldo intercepted Andres Iniesta’s slack pass across his own 18-yard line. As he attempted to go past Marquez, the Portuguese winger collided with the outstretched arm of the defender and tumbled to the turf but on this occasion the Swiss referee declined to oblige United.

The bluntness of Barcelona’s cutting edge in part reflected the fact that Rio Ferdinand was winning his personal battle with Samuel Eto’o and it was not until five minutes into the second half that the Cameroon striker finally escaped his shadow.

But after skipping past the England defender on the right of the box, his attempt to pick out Messi was thwarted by Michael Carrick’s important intervention. Two minutes later, Iniesta’s delightful little flick helped a pass from Messi into the path of Eto’o but, from a tight angle, his shot ended in the side netting.