As the fourth official held up his board to signify that there would be just two minutes of stoppage time, Old Trafford let out a collective groan. For the first time all evening, both teams appeared to settle for a draw, but then Wayne Rooney strode forward and unleashed a fierce shot to score his second goal of an unforgettable night, prompting the lustiest roar this stadium has heard in years.

Rooney disappeared under a heap of delirious team-mates, just as he had on the day he exploded on to the Premiership scene as a 16-year-old playing for Everton against Arsenal 4½ years ago. Here, a few months past his 21st birthday, he came of age, but so did a Manchester United team who fought their way back from the brink and will now go into the second leg of their Champions League semi-final at the San Siro stadium next Wednesday with confidence rather than the trepidation that briefly consumed them as Kaká overturned their early lead to put AC Milan 2-1 up.

It will not be easy, not with most of their defence still missing, but then it seldom is with United. In two decades in charge, Sir Alex Ferguson has often chuckled at his teams’ insistence on doing things the hard way, even flirting with disaster while chasing success on three fronts during the past few weeks. They did so again last night, their patched-up defence conceding two away goals that Ferguson described as “terrible”, but, as the dust settled on a pulsating evening, despite those two goals, their dream of emulating their phenomenal success of eight years ago had moved closer.

The parallels with 1999 are almost eerie. Now, as then, they must travel to Italy for a second leg that hangs in the balance. The Milan coach is Carlo Ancelotti, who was in charge of the Juventus team that led at Old Trafford for much of the first leg but was ultimately overwhelmed by United’s sheer will in the second. And, as in 1999, United will need to be selfless, even if in the case of Gabriel Heinze, Cristiano Ronaldo, Paul Scholes and Ryan Giggs, it means picking up a yellow card that would rule them out of the final, as Roy Keane and Scholes did in 1999.

Such concerns, though, are for another day. United had to show great character to remain in the tie, never mind in the ascendancy, having been stretched almost to breaking point by this vastly experienced Milan team during the middle chunk of the game.

Kaká scored twice, in the 22nd and 37th minutes, to overturn the early lead that United took through Ronaldo’s header, helped in bizarrely by Dida, and Ferguson admitted that Kaká could have scored at least once more in the second half. “That gave us a lifeline,” the United manager said.

It was another of those evenings when there was magic in the air at the Theatre of Dreams. Much of it came from Kaká, but this United side does not bow to the individual brilliance of others. Rooney, Ronaldo and Scholes grew in influence as the game drew on, but so did the unheralded Darren Fletcher. “Darren was outstanding,” Ferguson said. “He excels in big games.”

Fletcher’s first contribution was an over-hit pass, aimed at Patrice Evra, but his second, in the fifth minute, was important. A clever pass sent Rooney clear and, although Alessandro Nesta raced back to tackle the forward, United scored from the ensuing corner, taken by Giggs, Dida making a dreadful hash of it as he was hit full in the face by Ronaldo’s header, and, as the ball looped goalwards, succeeding only in touching it into his own net.

But, as much as United excelled in the first 15 minutes, they looked nervous when Milan were in possession. Andrea Pirlo set up Kaká for Milan’s first with a slide-rule pass in the 22nd minute, with the Brazilian sprinting past Heinze in the inside-left channel and beating Edwin van der Sar with an equally measured finish.

Fourteen minutes later, racing into the same area, Kaká put Milan ahead, this time all his own work as he lulled Heinze and Evra into a Keystone Cops-style collision before stroking the ball past Van der Sar for a second time.

During the ten minutes that preceded and followed the interval, United could have sunk, but cometh the hour, cometh the man, Rooney reacting sharply in the penalty area to beat Dida after an improvised pass from Scholes and, as Milan began to look stretched, United’s players grew in stature.

After 20 minutes of near-misses — Fletcher and Giggs coming closest to beating the erratic Dida — it seemed that the teams would meet in Milan next Wednesday with the scoreline level. But then Rooney summoned one last burst, striding forward and unleashing a fierce 25-yard shot that will stay with him for the rest of his days.