United were defending European champions, a year on from their treble season, but Madrid's 3-2 win at Old Trafford came with the message that football had already moved on. Ferguson admitted afterward he'd been tactically found out; Del Bosque famously talked of United's "tactical anarchy."
No sooner had Ferguson finally reached the promised land, than the map he used to get there was deemed indecipherable. For at least the fourth time at United he'd need to re-imagine his team and reconfigure his approach, and it would be eight years before Europe would feel the results.
Along the way United were six times dispatched in the Champions League knockout stages and once denied at the group stage. Madrid did for them again in 2003, with the other Ronaldo ("the older one, the fatter one" as Ferguson himself referred to the Brazilian on Monday) scoring a hat trick at Old Trafford in a 4-3 defeat that put the aggregate score at 6-5 to the Spaniards.
"The key was keeping them out and we simply couldn't do it," said Ferguson after a ridiculously attack-minded second leg had played out (BBC Sport).
United's transfer activity that summer reflected that fact. Strolling midfield creator Juan Sebastian Veron was deemed a luxury Ferguson could no longer afford; error-prone goalkeeper Fabian Barthez was replaced by Tim Howard; snarling fullback Gabriel Heinze was brought in to add some defensive desire.
But it was the sale of David Beckham to Madrid that would most alter United's destiny. Beckham was at the peak of his powers—a driving force in United's midfield who could run for miles and was technically as proficient as the best players in Europe.
Ferguson knew selling Beckham would be read as a failure on his part. Many felt the United manager was directly responsible for their unhappy relationship and blamed Ferguson for pushing Beckham out of Old Trafford. There was a fear United were now in the business of selling their best players and that Ferguson was letting his emotions get in the way of progress.
Ironically, Beckham's sale proved the most forward-thinking move imaginable—as it prompted the purchase of 18-year-old Cristiano Ronaldo from Sporting CP as his replacement and set United on a trajectory that would culminate in 2008 Champions League glory in Moscow.
It was no coincidence the teenaged Ronaldo was convinced to take Beckham's No. 7 shirt. And you don't need to read between the lines to see the message in Ferguson's reaction to his home debut against Bolton. After 29 minutes of dazzling wing play, Ronaldo was billed as United's future. Beckham was already in the past.
Said Ferguson in August 2003, as per BBC Sport:
It looks like the fans have a new hero. It was a marvellous debut, almost unbelievable. I felt his penetration could make a difference for us. We have to be careful with the boy. You must remember he is only 18. We are going to have to gauge when we use him.
Would United have signed Ronaldo if not for Madrid's move to sign Beckham? Quite possibly, but he wouldn't have got so much playing time in that first season and his development into a world-class attacking talent would have been more gradual.
So United have Madrid to thank for making Beckham a Galatico. They also have Madrid to thank for twice prompting Ferguson to reassess his tactical approach and helping shape the team he led to Champions League triumph in 2008—one set up with dramatically more defensive-minded approach.
The defeats in 2000 and 2003 were painful, but they were also educational. Ferguson realised it was no longer viable to run the attacking gauntlet and take his chances; he needed to tighten things at the back and in midfield and make his team harder to break down.
The 71-year-old takes those lessons into Tuesday's showdown and continues to evolve his thinking tactically. The United team that takes on Madrid on Tuesday will most likely be arranged in a nuanced 4-2-3-1 formation. Ferguson enters the match in the knowledge he won the battle of Xs and Os with Jose Mourinho at the Bernabeu and refusing to accept his age as a barrier to learning new tricks.
The old master leaned on Madrid's previous exploits at Old Trafford to plot a way toward 2008 Champions League glory. He also took their move to sign Beckham as a prompt to bring in a player who counts among the best—if not the best—he's had at United.
Ronaldo will be in opposition this time around, and it will take a defining effort from Ferguson and his team to stop him inflicting more Madrid misery on United.
Whatever happens on Tuesday, you can be sure Ferguson will learn from it. He always does.