Cristiano Ronaldo missed a second-minute penalty as Manchester United were forced to settle for a goalless draw in their Champions League semi-final first leg with Barcelona.

The Portugal international was handed a golden early opportunity to score the crucial away goal in the Nou Camp that Sir Alex Ferguson, the manager, and his side would surely have coveted.

Instead, Victor Valdes was not even called upon to make a save as Ronaldo side-footed wide of the goal.

A draw was just about the fair result in a match that never threatened to reach the heights promised of a meeting between two of Europe's most entertaining sides.

Barcelona were limited to a handful of opportunities, none of them clear-cut, while United, usually an irresistible attacking force were, by their standards, woeful on the counter-attack.

United could barely believe their good fortune when they won a penalty 85 seconds into the match, not that the award was fortuitous, but more that Milito, the Barcelona centre-back, could have been so foolish.

Ever ambitious, Ronaldo had tried his luck from fully 40 yards with a free-kick that took a deflection off the defensive wall and Paul Scholes swung in the resulting corner from the right.

Ronaldo flung himself at the ball and met it with a header and Milito, only a yard in front of him, instinctively flung up his arms and handled the ball.

Few would have bet against United’s leading scorer stepping up and slotting his 40th goal of the season, but he looked unusually nervy as he sidled up to the spot and sidefooted timidly wide. At first view it appeared he had missed the goal by a good few yards, but slow motion replays suggested the effort clipped the outside of the post.

That escape spurred on Barcelona to come at United, but for most of the first half the visitors kept the Spanish giants at arm’s length.

Gianluca Zambrotta fired in one cross from the right that necessitated a timely clearance from Wes Brown, playing in the centre of defence alongside Rio Ferdinand after Nemanja Vidic was ruled out through a stomach complaint.

Carlos Tevez fouled Yaya Toure in a dangerous position right on the edge of his own area, but Rafael Marquez smashed the setpiece straight into the wall.

Samuel Eto’o then found some space, but Wayne Rooney, who covered acres of ground during the course of the match without ever appearing threatening, hacked clear from inside his own area just as the Cameroon international was about to shoot for goal.

Just before the half-hour United felt, quite rightly, that they should have had a second penalty. Andres Iniesta played a careless ball across his back four which was easily cut out by Ronaldo, who raced by Marquez but was impeded by the experienced Mexico international.

One penalty to the visiting team at the Nou Camp borders on shocking, a second would have been a sensation and it was no surprise referee Massimo Busacca waved play on.

Brown made a desperate diving lunge to block an effort from outside the area from Eto’o while Marquez was booked just before the interval for tripping Ronaldo, a caution that will rule him out of the second leg at Old Trafford next Tuesday.

Barcelona continued to up the tempo after the restart and Edwin van der Sar was forced to tip a speculative 30-yard effort from Zambrotta over the bar.

Brown's slip two minutes later gifted Barcelona their clearest opportunity of the evening. He gave the ball straight to Eto'o who chose to ride a challenge from Ferdinand which, had he gone to ground, would probably have merited a penalty. Instead he continued but could not find the angle to pick out the unmarked Messi in the centre.

Moments later Messi and Iniesta set up Eto'o with some delightful interplay but the striker sliced wastefully wide.

United threats were rare, and when Michael Carrick did make some space for himself he blasted into the side-netting with players begging for the ball in the centre.

Thierry Henry, the former Arsenal striker, replaced Deco with 11 minutes to go and almost made an immediate impact. The France international cut inside from the left flank and tested van der Sar with a ferocious right-foot strike which the goalkeeper beat down with a little difficulty.

Van der Sar made another diving save from a long-range Henry free-kick two minutes from time, but this one was more for the benefit of the photographers behind his goal than out of necessity.