Lionel Messi was the difference between the two sides as Barcelona put one foot firmly on Wembley turf with a 2-0 win at the Santiago Bernabeu.
This was not an example of the beautiful game but a fierce encounter packed full of rash challenges, players swarming the referee and play acting that had Hollywood agents making enquiries.
Madrid, no doubt determined to constrict Barcelona and move into the second leg without conceding a costly away goal, employed defensive tactics with a midfield consisting of Pepe, Xabi Alonso and Lassana Diarra. There was no place for the weekend's hat-trick hero Higuain, nor Kaka, the other star of Saturday's 6-3 win at Valencia.
Barça had a fit-again Puyol leading the side at left back, while Mascherano continued in the centre alongside Pique and Keita came in for Iniesta.
Unsurprisingly, it was a cagey opening affair, the away side monopolising the ball but unable to create anything meaningful. Xavi had a sweetly struck long-range volley land safely in Casillas's arms before testing him again halfway through the first half when he latched onto a Messi through ball. From the right side of the area the angle was against him and he could only fire straight at the Madrid 'keeper.
Real fans would have been happy to see their side defending strongly but despite the presence of Ronaldo, Ozil and a dangerous Di Maria, attacking flair was limited and it was only on the stroke of half time that Ronaldo brought Valdés into the game with a speculative swirling effort. The Catalan shot stopper weakly fumbled the ball into the path of Ozil but the German international missed the follow up and was flagged offside anyway.
As the players walked down the tunnel there was a sign of things to come. Barça's reserve goalkeeper Jose Pinto got into a bout of handbags at dawn with a Madrid official and was shown a straight red card.
The second 45 minutes got underway in similar ugly fashion to the first. Late tackles were as common as Barça's theatrical dives and with Busquets, Alves and Pedro writhing around at one point or another, you would have thought you had switched onto something from Saving Private Ryan.
On the hour mark it inevitably boiled over. Ramos had already been shown a yellow that will rule him out of the return leg for a needless challenge on Messi but Pepe then went one further and was dismissed for a high tackle as Alves attempted to clear.
Though not as ridiculous as the sending off given to Van Persie when Arsenal visited the Camp Nou, the red card had many shaking their heads and a fuming Mourinho sarcastically applauding the referee on the sidelines. He would soon follow his Portuguese midfielder to the stands.
It was the forth 'Clásico' in a row that a Madrid player had been forced to leave the field early and Barça immediately began to capitalise. Pedro was inches away from opening the scoring with an instinctive rebound header after good play from Villa and then two minutes later the streets of Catalunya erupted.
Sharp play down the right from substitute Afellay bought him the necessary space to whip in a cross and an onrushing Messi needed no second invitation. The sacred left boot kissed the pacey cross as it sped across goal, deflecting it through the legs of Casillas and firing Barcelona into the lead. A one-goal deficit would not have been a bad result for Los Blancos, considering their 10-man status, but the World Player of the Year was far from done.
On 87 minutes Madrid fell silent and Catalunya practically jumped out of Spain. Picking the ball up from just inside the Real half, Messi did a Usain Bolt impression as he sped past three white shirts with one thing on his mind. Wondrous close control took the ball away from two further defenders and in the blink of an eye he finished off his solo move with a deftly executed right foot shot that was heading nowhere but the bottom corner.
It was Messi's 52nd goal this season and he would not have scored many better. His brilliance means Madrid must come from two goals behind at the Camp Nou; improbable to say the least and that's being generous considering the suspensions picked up by Pepe and Ramos and the touchline ban and perhaps even legal action that will be enforced on Mourinho.
Manchester United and Barcelona now look odds on for a repeat of the 2009 Champions League final. A small Argentine stole the show on that occasion as well and in this form, it's hard not to see history repeating itself. An unmissable spectacle is surely on the cards.