David Beckham had to settle for second best as the team he loves overcame the team he plays for in the San Siro.
Two second-half goals from the new Manchester United hero, Wayne Rooney, installs last season's beaten finalists as favourites to book a place in the Champions League quarter-finals.
Not even the concession of a third-minute opener for AC Milan, created by Beckham for Ronaldinho, could derail Sir Alex Ferguson's troops, although they were forced to endure some nervy moments at the end after Clarence Seedorf hauled Milan back into the tie five minutes from time.
It took a fortunate Paul Scholes effort to bring United level before the break.
But after surviving another spell of Milan pressure after half-time, Rooney stamped his class on the contest, scoring his first two European goals of the season to take his overall tally to 25.
In United circles, the summer of 2003 has become famous for Beckham's exit from Old Trafford.
Yet about a month after his move to Real Madrid was confirmed, there was an equally significant event involving Ronaldinho.
Ferguson was sure he had signed the Brazilian from Paris St Germain, convinced in his own mind every eventuality had been covered.
It was with some annoyance - mostly directed at former chief executive Peter Kenyon - Ferguson learned Ronaldinho had in fact signed for Barcelona.
As the alternative turned out to be Cristiano Ronaldo, perhaps the situation did not turn out too badly for the Red Devils.
But if Beckham had waited seven years to face his old club, United and Ronaldinho were hanging round for equally as long before their paths have crossed.
It took the former world footballer of the year just three minutes to remind Ferguson what he missed, after Beckham had done what everyone knows he can, produce excellent set pieces.
Patrice Evra's acrobatic attempt to clear that one set Ronaldinho up, although Edwin van der Sar had the shot covered before it deflected off Michael Carrick and ended up in the opposite corner.
For an old team, Milan clearly had something left.
Their passing had United twisting and turning, looking for all the world like a team on the edge of a very big cliff, not knowing precisely where the bottom was.
Ronaldinho, Luca Antonini and Klaas Jan Huntelaar twice came agonisingly close to finding Van der Sar's net again. If a couple of them had gone in, Ferguson could not have complained.
As it was, apart from Beckham, the only other 'Class of 92' graduate on the pitch was about to make a decisive contribution.
Scholes has peppered the intervening years with a number of howitzers, goals that will be admired decades from now.
This was not among them. Swinging at Darren Fletcher's low cross from the by-line, Scholes missed the ball completely with his right foot, the ball striking him half way up the shin of his standing left.
What could only be described as a freakish deflection not only took it the six yards to Dida's goal, but right in the bottom corner, giving the Brazilian no chance of keeping it out.
Milan's response was admirable, given what a shattering blow that away goal was, United's first in five away games against a fellow European heavyweight.
Andrea Pirlo forced a one-handed save out of Van der Sar with a 30-yard free-kick, then the 39-year-old Dutchman required every inch of his massive frame to flick a goalbound Ronaldinho effort round the post.
Yet in that one stroke of good fortune for Scholes, it seemed the destiny of the tie had been shaped and a minute after what turned out to be an inspired substitution, Rooney break his European duck.
Antonio Valencia, who had just replaced Nani, was the provider, sending over a cross from the right that allowed Rooney to steer a header back over Dida into the opposite corner.
Now the age in Milan's legs began to tell. And when Darren Fletcher chipped another cross into the box, Rooney stole between defenders to head home once more.
It seemed victory and progress was assured, so Ferguson will be livid at the Seedorf effort five minutes from time that ensured an uncomfortable ending and gives Milan a flicker of hope for the return in three weeks' time, when Michael Carrick will be unavailable following his dismissal deep into stoppage time.Reuse content