All the attention may be on Cristiano Ronaldo tonight, as Real Madrid’s best player takes on his old team, Manchester United.
But Borussia Dortmund have already played Los Blancos in the Champions League this season, and their manager, Jurgen Klopp, has a helpful word of advice for United boss, Alex Ferguson.
The in-demand German says United must stop Real playmaker Xabi Alonso if they hope to derail the Spanish champions.
Dashing Dortmund beat Real 2-1 at home and drew 2-2 with them at the Bernabeu, to finish as winners of the ‘group of death’.
And Klopp says it was their ability to cut off Alonso’s raking long-ball game that allowed them to neutralise Real’s attacking threat.
And so Klopp says if he was Fergie, Alonso would be the man in his line of sight.
"We knew where they would send their passes, how they look for Cristiano," Klopp said.
"Our plan was to take Xabi [Alonso] out of the game. Because if Alonso can play as he wants it is impossible to defend against Madrid. And [Mario] Gotze covered him.
“We knew that if our full-backs, [Lukasz] Piszczek and [Marcel] Schmelzer, moved around a lot, the advantage would be on our side against Cristiano.
“If you block Xabi, you make it so Pepe always has the ball. That is a big difference."
Meanwhile, Klopp has revealed that Real’s ‘Galactico’ era was one of his main focal points as an up-and-coming young manager.
But that Barcelona have now taken that awesome Real Madrid’s line-up to another level.
"[My biggest inspiration was] the white ballet, Real Madrid of a few years back," Klopp explained, ahead of Dortmund’s Champions league last-16 tie against Shakhtar Donetsk on Wednesday night.
"Then I thought: If you take this footballing potential and add a defensive plan … you would have the perfect team. And Barca did that."