Real Madrid will attempt the improbable when they look to overcome a 4-1 deficit against Borussia Dortmund in the second leg of the Champions League semifinals.

Robert Lewandowski and Dortmund were in brilliant form against Real in the first leg at Westfalenstadion, and already have one foot in the final at Wembley following their 4-1 first leg win.

However, Jose Mourinho is confident his side can achieve the impossible against the German side, which have been so impressive this season.

"I feel this is the most important match in ten years for Real Madrid, but I also felt that in Dortmund and we played like (it was) a friendly," Mourinho told reporters. "I've already said everything to my players.

"The most important thing was to talk about the mistakes we made in Dortmund. At most clubs success belongs to everyone and failure to the coach. Sometimes football is not fair to one team, but it was in Dortmund and Borussia deserved to win. Anything is possible though."

Dortmund coach Jurgen Klopp is taking nothing for granted despite the big lead, and promised his players would not relax in the second leg at the Bernabeu.

"We thrilled our fans in the first leg and everyone knows how we can play but let's see what happens," he said. "Madrid will try everything. We are not in the final but the first-leg result was better than expected.

"We will have to fight tomorrow (Wednesday) with all our strength. It would be silly for us to have a clear idea of what we are going to do as Madrid can pose us problems. We have great attacking potential and we proved that in the first leg.

"The team needs to be disciplined and compact while also looking to be daring. Anything can happen in football. We must concentrate on what happens out on the pitch tomorrow. I fully believe my team will play correctly and we will be hard to beat."

Real Madrid superstar Cristiano Ronaldo has been declared fit after missing the Madrid Derby against Atletico at the weekend due to a slight thigh strain. Alvaro Arbeloa and Marcelo, however, are ruled out through injury. Fullback Lukasz Piszczek is a major doubt for Dortmund.

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Expected lineups: Real Madrid: Diego Lopez; Ramos, Varane, Pepe, Coentrao; Khedira, Alonso; Di Maria, Ozil, Ronaldo; Higuain.

Borussia Dortmund: Weidenfeller; Piszczek, Hummels, Subotic, Schmelzer; Gundogan, Bender; Blaszczykowski, Reus, Gotze; Lewandowski.

Prediction: 4-2 to Real Madrid