Carlo Ancelotti is having trouble defining his preferred starting eleven. So far, the Italian has been switching players depending on the rivals’ characteristics, and that might be one of the reasons why Real hasn’t found their game style yet.

The Clasico against Barcelona will be a tricky test for Ancelotti. His decisions will be crucial for Los Blancos to annul the Azulgranas’ brilliant combination football or succumb to their arch-rivals.

It is always difficult to tell what would be the best starting eleven to face such a great squad, but here are some clues about the line-up we might see on Saturday:

Goalkeeper: There is no doubt Diego Lopez is going to start. Iker Casillas beat his personal record against Juventus, reaching 520 minutes without conceding a goal, but Lopez is Ancelotti’s choice for La Liga and he is also in excellent form.

Full-backs: While Marcelo is guaranteed to start at the left-back, there is a debate over who should play on the right. Ancelotti has usually picked Alvaro Arbeloa when facing stronger teams, and that will probably be his choice. However, Daniel Carvajal could be a good option too. The youngster is faster than Arbeloa, and that could help stop Neymar, who is enjoying one of the best moments of his career right now. Real would be more dangerous in counter-attacks, and could also cause more trouble to Barcelona’s weakest point: the left-back.

Centre-backs: It would be a surprise if Sergio Ramos and Pepe didn’t make it in the starting eleven. Ancelotti could consider replacing the Portuguese with Raphael Varane, but the Frenchman is in poor shape after returning from a long-time injury and Pepe is putting in some very good performances lately. A surprising option would be including Pepe as defensive midfielder to stop Leo Messi, just like Jose Mourinho used to do, but that seems very unlikely to happen with Ancelotti in the dugout. Nonetheless, if Varane was perfectly fit, I would certainly consider it.

Centre-halves: Against Juventus, Carletto picked a defensive pair –Asier Illarramendi and Sami Khedira– in order to contain the Italians powerful midfield. However, that didn’t work well, and Real lacked a playmaker who could keep the ball and organise the attacks. With Khedira seeming to be untouchable under Ancelotti, the inexperienced Illarra could sit on the bench leaving his spot to Luka Modric. However, that would certainly worsen Real’s defensive efficiency. Against such a potent midfield, maybe Illarramendi would be a better choice.

Attacking midfielders: It is obvious that Cristiano Ronaldo and Angel di Maria are going to start. There were rumours about the Argentinian being left out to accommodate Gareth Bale, but El Fideo has certainly earned it with his brilliant performances. The main issue is who from Isco, Bale or Modric will join them. In case the Croatian starts in central midfield, Isco would probably be the playmaker. Nevertheless, it wouldn’t be surprising to see Ancelotti opt to take advantage of Bale’s physical condition to contain Barca’s offensive full-backs. I would personally pick Modric, who seems to be in better shape and could put Victor Valdes in trouble with his precise long-distance shots.

Striker: This is probably the main discussion among Bernabeu’s crowd in the last few weeks. Karim Benzema seemed to have returned to form, scoring two goals with France and showing more commitment to help out the defence. But he had a terrible game against Juve and was booed by the fans. With Alvaro Morata in such a great shape, I personally think Benzema could benefit from spending some time on the bench. It is risky to line-up such a young player in such an important game, but at least he exert a very high pressure on Barca’s defence and even help cutting pass lines in the midfield. Benzema has already had many chances. Morata deserves at least one.