Zinedine Zidane suffered his first defeat as Real Madrid coach as Antoine Griezmann gave local rivals Atletico Madrid a 1-0 victory at the Bernabeu.
The Frenchman struck in the 53rd minute to inflict a fourth league derby defeat in six games on the Merengues, who have not managed to beat their local rivals in the Primera Division since 2013.
Atletico were just about worthy winners of a typically tense and tight derby, although Real felt they should have been awarded a penalty in the second half for a trip by Atleti captain Gabi on Danilo.
Real had scored 20 goals in their previous four matches at the Bernabeu but have been chaotic of late in defence, conceding 24 goals throughout the season.
Atletico, meanwhile, boast by far the best back line in the league but have left much to be desired at the other end, failing to score in four of their last eight matches. They had scored just 35 goals all season in the league, less than half of Real's tally.
They arrived at the Bernabeu less than 72 hours after playing out a goalless draw at PSV Eindhoven but Diego Simeone made just three changes, bringing back Jose Gimenez, Fernando Torres and Augusto Fernandez.
With Marcelo ruled out with injury, Danilo deputised at left-back for Real, and Zidane employed both James Rodriguez and Isco in midfield, dropping Jese to the bench.
There was a cagey start to the game save for a couple of hopeful efforts from either side. Atletico slowly began to impose themselves on the hosts with a high pressing game which resulted in Torres finding space by the near post, but the defence just closed him down in time and Keylor Navas was able to scoop up the ball.
Cristiano Ronaldo then let fly from a free kick, forcing Jan Oblak to repel, and the loose ball eventually fell at the feet of Karim Benzema who flashed a shot wide of the far post.
Raphael Varane also missed the target with a flicked header but Atletico finished the half stronger, Griezmann forcing Navas to tip his stinging shot over the bar and Koke unsuccessfully trying to squeeze the ball past the Costa Rica goalkeeper at the near post.
Benzema was taken off at half-time with a suspected injury, replaced by 18-year-old Borja Mayoral, who shone for Real's under-19 team in their 3-1 UEFA Youth League win over Manchester City.
Ronaldo tried to give his side the lead just after the restart with a low drilled effort, but missed the target.
Atletico broke the deadlock a few minutes later, Griezmann exchanging passes with Filipe Luis as he approached the area and then shooting low beyond the diving Navas, scoring his first league goal since January 17.
Saul Niguez might have killed the game off when he bore down on Navas, but the goalkeeper came out bravely to block his shot.
Real could only respond with tame efforts, such as one from Mayoral that Oblak comfortably tipped away, and a header from Ronaldo which landed in the arms of the Slovenia goalkeeper.
Their frustration grew when Danilo went down in the area under a challenge by Gabi and the referee refrained from awarding a penalty, and Atletico hung on to claim their third successive league win at the Bernabeu.