"You can always learn something," Mourinho said, though, of his presence at the fixture.
As for Cristiano Ronaldo, Real's ace in a deck full of kings, it was Sir Alex and his coaching staff who nurtured the no.7 from raw talent to world beater. If there's anybody who knows how best to tame Madrid's goal machine it's the man who helped create him.
It's not just Ronaldo the United players and staff are familiar with. The Reds faced Ricardo Carvalho, Alvaro Arbeloa, Luka Modric, Michael Essien and Xabi Alonso countless times in the Premier League, while Raphael Varane, Fabio Coentrao, Mesut Ozil and Karim Benzema have all been heavily linked with moves to Old Trafford in the past. You can forget about the element of surprise.
The sheer enormity of this tie and what's at stake – a place in the Champions League quarter-finals, no less – is also likely to breed caution. After all, the team that makes the fewest mistakes in a game of football usually wins. And the easiest way to make the fewest mistakes is to not take risks.
We've all seen cup finals where teams are more afraid of conceding than they are concerned with scoring, and United, with the advantage of playing the second leg at home, could conceivably adopt a spoiling, conservative approach. It may even be wise.
Of course, not all big games fail to live up to expectations. United and Chelsea, for instance, have served up some classics in recent years (including the 2008 Champions League final when stakes were at their very highest) and we've all tuned in to enough El Clasico fixtures to know Real Madrid can also turn it on when it matters most.
I sincerely hope we witness something remarkable, a spectacle to tell future generations about. But don't be surprised if Wednesday's match doesn't quite reach those lofty heights. At this stage, the tactical battle isn't so much about devising a plan to beat the opponent but making sure you don't lose. And if United can achieve that, it will be a result worth celebrating. Until then, all we can do is wait.