These were set to be eight decisive days – Barcelona away, Barcelona at home and Manchester United away – but the threat was always a promise too and here it was fulfilled, the first hurdle overcome with ease, over almost as soon as it had begun.
With the score 2-0 to Madrid on the night, 3-1 on aggregate, the Catalans were left to play the final half an hour more out of obligation than anything else. And then with 68 minutes gone, Raphaël Varane headed the third to bring José Mourinho's finger to his lips and make this another brilliant night. Jordi Alba's goal was irrelevant, clinched in the 88th minute before a half-empty stadium.
As the injured Madrid goalkeeper Iker Casillas said ominously afterwards: "This gives us more hope and confidence for the rest of the season: hopefully it can prove a turning point. We never really suffered tonight."
When it comes to head to head matches against Barça, Mourinho's Madrid have become the better side: the past six meetings have seen Madrid effectively clinch the league, win the Spanish Super Cup and now claim a place in the Copa del Rey final, as well as drawing 2-2 here in October. Ronaldo too has become more dominant than Leo Messi.
Trailing by 16 points, the league is Barcelona's but that did not feel like it mattered much here: this was humiliating for the home side, worrying too. The sheer speed of Mourinho's team was breathtaking. A place in the final brings with it confidence that they can win at Old Trafford in the Champions League. Barcelona, by contrast, know that on this form they have no chance against Milan. They were impotent again.
Madrid got the goal that changed the complexion of this tie before the quarter-hour mark and it was a portrait of the two sides. At times it appears to take little to score against Barcelona. The worrying thing from the perspective of Sir Alex Ferguson, here to watch the game, was how swiftly and unexpectedly Madrid can plunge the dagger into your heart.
At one end, Messi was bundled over by Angel Di María but as some Barça players appealed for a penalty, they wasted the free-kick. Suddenly, at the other end they were exposed. Ronaldo was running at Gerard Piqué; one step-over, two, and the defender was drawn in to a foul. This time there was no doubt and Ronaldo coolly rolled in the penalty, making this the sixth consecutive trip to the Camp Nou in which he had scored.
It was also the 12th consecutive game in which Barcelona had conceded and their task was now huge. Trailing 2-1 on aggregate, the away goal advantage gone, they were on a knife edge. Mourinho had the game where he wanted it. Barcelona had to score but knew that another Madrid goal and they would need three. It rarely looked like they would get even one. Messi dropped deeper, largely ineffective, Cesc Fábregas was lost and there was no presence in the area.
Messi's free-kick flashed just wide and Pedro Rodríguez felt he had been bundled over by Xabi Alonso but the few saves Diego López had to make were routine and when Madrid broke they did so with intent, led by Mesut Ozil and Ronaldo. If Barcelona began the second half with renewed intensity their efforts were stillborn. Sergio Busquets brought a sharp save out of López and Andrés Iniesta's shot was charged down when the ball dropped to him from a corner but a second later it was effectively all over.
A long ball from Sami Khedira, Di María ran at Carles Puyol and José Pinto saved his shot only for the ball to drop to Ronaldo, who brought it down on his chest and finished Barcelona off. There were 32 two minutes left but the cup tie was over.
On the touchline, David Villa had been warming up as the fans chanted his name and now he came on but it was too late, Varane powering home a header just as he had done in the first leg. When Alba scored it simply did not matter.
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image: © Jan S0L0