May 16th will mark the fourth time this season that Real Madrid face Barcelona. The stakes will be higher, the game will take place outside of Spain and a couple of injuries could alter the rotations of both teams. However, the first three versions of this season’s clásico offer plenty of material for a Euroleague semifinal preview.

Numbers indicate that the two Spanish giants find it difficult to stop each other from scoring.  Madrid’s triumph against the blaugrana at the London final four was based on an inspired defensive performance in the closing minutes of the game, but the Spanish champs have not been able  to reproduce it this season. Barcelona scored a little over 106 points per a hundred possessions in their three meetings with the second-best defense in Euroleague. This number could have easily been a lot more impressive had they not missed 12 free throws – not to mention a few great looks from behind the arc – at the Copa Del Rey final. The main reason for Barcelona’s success on the offensive end is their pick and roll execution:

Marcelinho Huertas in particular has been a force in the middle of floor, making shots and dishing out assists in the area which extends from the three-point line to the free throw line. Madrid’s defense enables him to get to his spots, as their big men are limited to a “show and get back” defense which hardly stops the ball and fails to close the passing lane toward the roll man. And when the weak side defender rotates deep to help the helping center, Barcelona have been able to generate more than a few open looks from the corner and the wing. Madrid have tried to counter with a more aggressive approach, designed to prevent Huertas and the other Barcelona ball handlers from turning the corner and getting to the middle of the floor. This strategy opens up a driving lane on the opposite side of the ball screen, but it provides help defenders with more time in order to complete their rotations. However, stopping the ball is still a challenge for Pablo Laso:

The possible absence of Dontaye Draper (who fractured his arm in game 1 of the playoffs) will certainly impact Madrid’s defense on the ball. In any case however, it is evident that the merengues rotate more than they would like to. Ante Tomic is very dangerous on the short roll, both as a passer and a finisher a few feet away from the hoop. This means that Madrid center need to be very quick on the feet. Sounds like a job for Marcus Slaughter, who has had an uneven Euroleague campaign but remain the best pick and roll defender of his team.

Then again, Madrid could win this game by simply outscoring Barcelona. Xavi Pascual has not managed to build the defensive wall of previous season, but his team still gets more stops than most. This has not been the case against Madrid, who continue to capitalize on a series of mismatches, making the blaugrana defense look average at best. The most talked about example of this trend is the way Laso attacks Juan Carlo Navarro, who could be in for a long night given his questionable fitness after the leg injury he picked up against Galatasaray. But the power forward position has proved an even more noticeable chink in Barcelona’s armor:

No matter who plays the four for the blaugrana, and no matter what Madrid run on their offense, Nikola Mirotic and Felipe Reyes have been devastating. Erazem Lorbek, Bostjan Nachbar and Macej Lampe have looked clueless for the most part: they can’t defend the pick and roll, are not serviceable as help defenders, do not box out effectively, need all the help they can get in post up actions and cannot keep up when their opponents attack off the dribble. They are only so many schemes that Pascual can draw up in order to cover for those deficiencies. Given the familiarity between the two teams, there is very little room for tactical surprises. Both coaches have implemented at times their favourite variations of zone defense – Laso going with a zone press led by Slaughter’s defense on the ball and Pascual bring out his trusted 2-3 formation:

In these situations, Barcelona run the risk of being spread thin on the perimeter. All it takes is a quick entry pass, and suddenly the zone has a weakside problem:

On this play, Slaughter found Mirotic on the far corner for an open three. It is clear that Huertas should have rotated toward Carroll on the right wing. But if one looks at the big picture, Pascual’s zone has the same objective as the Olympiacos switch defense which slowed down Madrid for two games and a half: always have a defender in front of Madrid’s perimeter shot creators and force the big men to make more decisions than usual. Even when Barcelona were defending man to man, Pascual often tried to crowd the ball handler:

Again, this approach is not without risks, given Madrid’s efficiency from three-point range. And Barcelona’s big men are not mobile enough to chase the likes of Sergio Rodriguez in the perimeter for extended stretches. But those blitz tactics could pay dividends in key moments of a knockout game. Madrid, on the other hand can probably take more risks with Barcelona’s perimeter shooting, given the inconsistency of the blaugrana in this area. But they still need to improve their pick and roll defense.

The fact that there are no secrets between those two teams could actually make this semifinal even more exciting: if a tactical adjustment by either coach makes a noticeable difference, then it will have to be something really special. The individual effort which will be required by the players of both teams in order to overcome such a well-prepared opponent should also be remarkable. And overall, this promises to be a balanced game. Madrid have been the best team in Europe all season, but Barcelona  lost the most important duel so far ( that would be the Copa Del Rey final) due to their own shortcomings, not because they were outplayed. And while it is understandable that watching the same group of teams compete for the Euroleague title year after year can take away some of the excitement, this game should be special.