Before kick-off, all the hype surrounding United's meeting with Real was all about a certain returning prodigal son, but instead two hot debates emerged.
The decision by Sir Alex Ferguson to drop Wayne Rooney at the expense of Nani received nervous retorts of 'we hope you know what you're doing', whilst referee Cuneyt Cakir was issued with angry bellows of 'you don't know what you're doing' upon his decision to send the winger off.
Ignoring everything else for a moment, the fact that the aftermath of one of the biggest games of football in recent years has been completely overshadowed by a refereeing decision is a great shame for the players, the fans, and the viewing public.
At half-time, and even after United took the lead through a Sergio Ramos own goal, the game was beautifully poised. United were seemingly in control with 55 minutes on the clock, but the quality of the opposition meant the game was far from over.
It was simmering nicely, Real dominated possession but United were dangerous on the break. Ryan Giggs - whose 1000th appearance for the club has almost been forgotten about - was exceptional, whilst the occasion seemed to be getting the better of the returning hero Cristiano Ronaldo. The home fans were magnificent, whilst the Los Blancos following were doing their best to be heard too.
It was all set up for a fantastic finish - and then was completely ruined in a moment. Regardless of the side of the fence you sit on - whether you blame a poor judgement call from the referee, or a misguided challenge from Nani - the curtain came down early on the show.
As much as opinions on the outcome were split going into the fixture, the debate on the dismissal has been equally varied. Roy Keane claimed 'the referee has actually made the right call. It's dangerous play - it's a red card', whilst Dietmar Hamann suggested it was 'not even a booking'.
The majority feel the sending-off was extremely harsh and the wrong decision. Nani's intention appears to be to reach only for the ball; as his transfixed eyes show on replay, he seemed entirely unaware of the approaching Alvaro Arbeloa.
Whilst it has to be recognised that the referee didn't share the advantage we do of a replay system (which brings up another argument), the manner in which Nani shaped his body suggested that was not malicious intent.
Ticking off, yellow card, magic sponge for the Spanish full-back, and then on with the game. Perfect.
But alas, that wasn't to be. It's incredible that a judgement call made by a single man lessened the experience for 200 million people watching worldwide. Although I vehemently agree that the call was a bad one, Cakir should be recognised for at least having the courage to make it in the first place.
However, to purely draw focus on the sending-off is somewhat short-sighted. In fact, the Turkish referee had earlier missed a clear claim for a Real penalty when Rafael's arm blocked the ball on the line (something which ITV happily glossed over), United had chances over the two legs through Robin van Persie, Nemanja Vidic and Danny Welbeck to take a firm grip on the tie, and instead of galvanising after Nani's dismissal, the home team appeared to be feeling rather sorry for themselves.
The latter point may seem harsh considering the circumstances, but it's been said on many occasions that playing against 10 men can be tougher than 11 as players tighten, defend stronger and draw off spirit.
After all, United still had the advantage and players to capitalise, and - as Mr Mourinho so diligently said himself - Madrid were not at their best.
But c'est la vie. United and Sir Alex will be back next season, and although the Scotsman may be 'distraught' at the moment, it's extremely unlikely to be a defining moment for his career or the club. The same cannot be said with such conviction for Rooney though.
In the previous encounter between the teams at Old Trafford in April 2003, Fergie also made a big statement about his team by leaving David Beckham on the bench. "I was on the outside looking in. 'Real Madrid: an important game, son. Too important for you to play in.' I could taste the anger in the back of my throat," admitted the former England captain. We all know how that ended.
It's easy to jump on the bandwagon and say that Rooney's days at United must be numbered then. Perhaps it was recognised that all of his last eight Champions League goals had come away from home, and that the last time he scored at home in the competition was three years ago. It's also extremely likely that Fergie favoured Nani in a wide role as it gave the team pace on the break and prevented Arbeloa from striding forward. Even after the sending-off, there has been no suggestion that Ferguson got it wrong.
Though things haven't quite been right between the player and club for some time now, the Liverpudlian will be fuming that he was overlooked for a game of such magnitude. In October 2010, it was a completely different story as the Glazers sought to assure their star player personally that the team matched his ambitions and were making strides.
But he is no longer the focal point of the team, and whilst his return of 11 Premier League goals this season is reasonable, his nine assists demonstrate he is more involved as a supporting cast member now. The truth is that Rooney is no longer indispensable, and the likes of Radamel Falcao, Neymar or Robert Lewandowski are becoming increasingly attractive names if the money can be freed up.
It will be interesting to see how United, Ferguson and Rooney all react to Tuesday night as the season draws to a close. Without question, the team and manager will get the opportunity to right a perceived wrong again next season - but whether Rooney will be there to assist is perhaps the bigger talking point.