It was an epic night and, by the end, Manchester United might be emboldened enough to reflect they have made the first decisive move. Sir Alex Ferguson's team may have to be more ruthless in the second leg. They will also need to think again when it comes to trying to muzzle Cristiano Ronaldo but this was still an encouraging night for the Premier League leaders and it is typical of how they played that they were so aggrieved at the final whistle.

The mob of players in red shirts who gathered around the German referee, Felix Brych, to complain he had blown for full-time before they could take a corner were aghast because these were moments when they were threatening to win the match. They were frustrated because they had passed up three wonderful chances to register one of the great results of Ferguson's quarter of a century at the club. Ferguson had promised they would play with ambition and in those final exchanges, when another team might have settled for a draw, they were still pressing forward in the old United traditions.

They had been subjected to some intense pressure from José Mourinho's team. David de Gea put in the kind of performance that makes it clear why Ferguson will tolerate the goalkeeper's occasional lapses and, with Ronaldo in this mood, the return leg will always have its dangers. Ronaldo was brilliant, such an elusive and devastating opponent. He almost won it with a dipping, swerving free-kick from 40 yards and his equaliser, 10 minutes after DannyWelbeck had opened the scoring, sets up another enthralling occasion for 5 March.

Yet Ferguson was entitled to argue his team might have left Madrid in a greater position of strength. Robin van Persie was wasteful with two opportunities in quick succession and, for the second, a surer touch would never have allowed Xabi Alonso to clear off the goalline. Ryan Giggs, a substitute who entered the pitch to the kind of applause the Bernabéu reserves for only a select few, also had the chance to win the game. United will just have to hope those misses do not come back to haunt them because Mourinho had a fair point when he said Madrid could score at Old Trafford. "Many teams have already done that this season," he said.

The trick for United, once again, will be to balance their normal sense of adventure with strategic conservatism. They had Phil Jones in midfield here to prove extra cover for Rafael da Silva against Ronaldo. Wayne Rooney could be seen tracking back from the right side of attack. Ferguson, in other words, had three players under specific instructions to subdue their old superstar. Even then, Ronaldo was a brutal opponent. Once again, he demonstrated to the watching world that a superstar at his level is not fazed by smothering tactics. Ronaldo has a rare ability to find space and elude the most careful planning.

Yet there were other moments that will offer United encouragement ahead of the return leg. Madrid's vulnerability when defending crosses was not just evident for Welbeck's goal. The same player also came close to scoring again after Van Persie's left-wing cross. There was the sight, early on, of Raphaël Varane trying to head the ball back to his goalkeeper and succeeding only in conceding a corner. Varane was lucky not to be sent off later on after colliding with Evra, as the last man, and Welbeck's goal was so straightforward it brought a disbelieving Mourinho to the touchline, gesturing his horror. Madrid have been poor at defending corners all season and, once Rooney had swung the ball over, Welbeck exposed this weakness by holding off Sergio Ramos and flashing his header past Diego López.

The more worrying aspect for Ferguson was the frequency with which Da Silva looked susceptible on the right side of defence. It was not just Ronaldo who menaced the youngest member of United's defence. Mesut Ozil played with great distinction during those moments in the first half when virtually all of Madrid's attacks started on the home side's left.

Ferguson had left out his usual captain, Nemanja Vidic, on the basis that it would be over-exerting him after his knee issues. Instead Jonny Evans partnered Rio Ferdinand whose performance, once again, demonstrated how eccentric it is that he is excluded from England's plans. Da Silva, to give him his due, improved in the second half and De Gea deserved all the acclaim that Ferguson reserved for him after the match. The young Spaniard might invite scrutiny sometimes but he has an incredible knack of getting his fingertips to shots and he was in exhilarating form. He had to be because Madrid attacked from all angles.

As for Ronaldo, he managed to terrorise Ferguson's team and still get a bearhug from his old manager. His goal was a classic. Angel di María whipped his cross into the penalty area and, after that, it was a demonstration of Ronaldo's prodigious ability to leap for crosses, like a centre-forward from another era. "I blamed Patrice Evra at first," Ferguson said. "But then I saw the replay and felt stupid. Watch it again. Ronaldo's kneecap is the same height as Evra's head. It's phenomenal. I don't think there's another player in the world who can do that."