Mourinho got his tactics spot on Saturday night. Real Madrid were the better team, and it was largely due to The Special One's tactical setup.
Los Blancos played their standard 4-2-3-1 (or 4-3-3 depending on how you categorize it) formation, but Mourinho slightly tinkered with the system in order to stop Barcelona.
In past Clásicos, the Portuguese tactician opted to sit deep and absorb pressure, with the back-four dropping to the edge of their own penalty box. However, on Saturday night, Mourinho set out his team with a high defensive line of pressure.
This higher defensive line condensed the midfield, making it more difficult for Barcelona to penetrate into the final third and easily keep possession around the penalty box. In addition to the high line, The Special One organized the team in a significantly more compact shape. The defensive line, midfield line and forward line were all close to one another. At times, it seemed as though Benzema and Pepe were only 30 meters apart.
From a tactical perspective, it seems that Mourinho wanted the team to stay compact for two reasons. First, by keeping all three lines close together, the number of players in such a concentrated area congested the midfield and shut down passing lanes. This tactic forced Barcelona to play square and negative passes.
Secondly, the compact team shape also helped Madrid on the counterattack. By keeping the likes of Benzema and Ronaldo close to the midfield and defensive line, Madrid's attackers were less isolated on the counter. The Frenchman was able to link up with teammates and transition into the attack with more numbers than in previous Clásicos.
While Los Blancos were able to initiate counterattacks by quickly combining with teammates and releasing players into space, the compact shape opened up more space in behind Barca's defenders as well.
Possession statistics would suggest that Barcelona dominated the match. However, Real Madrid were the team in control, as the home side struggled to cope with the high line and compact shape.