Pep Guardiola is a managerial genius and always will be for his numerous achievements with Barcelona, but one has to question a couple of the decisions he made versus Los Blancos.
First, where was Gerard Pique. In fact, where has Gerard Pique been? For some reason, Guardiola has consistently stuck with Javier Mascherano as his center-back of choice alongside Carles Puyol, despite Pique being comprehensively better than the Argentinian.
Unlike Mascherano, Mr. Shakira is stronger in the air, a much better passer of the ball, and more dangerous up front. Mascherano isn't bad, but he could've been the man to prevent Pepe's header in the first half, which led directly to Real Madrid's opening goal via Sami Khedira's tap-in.
Second, why did Cristian Tello start over Alexis Sanchez—or Pedro and Cesc Fabregas for that matter? Neither Fabregas nor Pedro have been in great form as of late, but Guardiola threw Tello into the deep end by starting him in this match.
Tello's game is still overly simplistic. He'll receive the ball, cut inside or straight ahead of his defender, and unleash or a shot or a cross. His dribbling, decision-making and ability to link up with his teammates all still need improving, and El Clasico wasn't the stage for that improvement to occur.
Finally, when Tello's struggles were apparent in the first half, why did it take until the 81st minute to take him off?
If he'd been taken off prior to the 70th minute, when it was clear to everybody that he was the player struggling most in the game, his replacement could've helped Barcelona mount a comeback.
Instead, Tello's substitution came after Cristiano Ronaldo's goal had demoralized Barcelona, and Guardiola's players had effectively lost interest in the game, knowing that even a 2-2 result wouldn't help Barcelona get back in the title race.
Hopefully we'll get some answers from Guardiola, at least regarding Gerard Pique's continued omissions. His absences are seriously hurting Barcelona.