Atletico Madrid have beaten Real Madrid at the Bernabeu in La Liga for a third successive season after Antoine Griezmann's second-half effort secured three vital points for the visitors on Saturday afternoon.
Real Madrid entered the match without first-choice left-back Marcelo, but Karim Benzema returned from a hip problem to start in the final third alongside Cristiano Ronaldo and James Rodriguez.
As for Atletico, Yannick Ferreira Carrasco and Stefan Savic both missed out, but there was a return in central midfield for Augusto Fernandez, while Fernando Torres was chosen ahead of Luciano Vietto as the centre-forward.
Real Madrid made the brighter start to the match and Ronaldo showed his intent inside two minutes with a strike from distance, but his effort was always moving wide of the post.
Atletico's first half-chance came in the 11th minute when the returning Fernandez had a go from outside the box, but like Ronaldo, the midfielder was never really testing the opposition goalkeeper.
Raphael Varane was next to come close for the home side after meeting a deep Toni Kroos free kick in the 17th minute, but the French international's header was high of the crossbar as a tight match remained level.
Indeed, the opening 30 minutes passed without either side creating a clear-cut opportunity. As expected, it was Real Madrid in possession of the ball, with Atletico sitting deep and attempting to threaten on the counter-attack.
Ronaldo struck a dangerous free kick towards the top corner in the 32nd minute as Real Madrid came close to scoring, but Jan Oblak was on hand to make a smart save, before Benzema fired wide of the post.
Atletico's best chance of the first period fell to Griezmann five minutes before the break, but the Frenchman's effort was saved by Keylor Navas, before the goalkeeper got down to keep out a strike from Koke as the capital rivals entered the half-time break at 0-0.
There was a change for Real Madrid at the break, with 18-year-old Borja Mayoral replacing Benzema, who did not appear fully fit in the first period after only just returning from injury.
The first chance of the second half fell to Ronaldo in the 48th minute, but the Portuguese fired just wide of the far post after some rare slack defending from the visitors.
It was Atletico that took the lead in the 53rd minute, however, when Griezmann combined with Filipe Luis before picking out the bottom corner to score his first league goal in six matches.
Saul Niguez had the opportunity to make it 2-0 in the 66th minute during a period where Real Madrid were in control of the possession, but the midfielder could not beat Navas from close range.
Ronaldo remained Real Madrid's main threat as the contest headed for its final 20 minutes, but the attacker could not beat Oblak from a close-range header, before the Atletico stopper kept out Mayoral.
In the absence of Gareth Bale and Benzema, Ronaldo continued to take charge for Zinedine Zidane's side, but the Portuguese could only head at Oblak in the 85th minute as Atletico's back four, marshalled by Diego Godin, remained unmoved.
Danilo also came close for Real Madrid late on, but the full-back fired wide as Atletico secured three vital points and all but ended Los Blancos' already-slim title hopes in the process.
The victory means that second-placed Atletico are now unbeaten in their last six league games with Real Madrid and have opened up a four-point lead over Los Blancos in the La Liga table.
Atletico have also closed the gap on league leaders Barcelona to five points, but Real Madrid remain nine points off the summit ahead of the Catalan side's game in hand, which is at home to Sevilla tomorrow.
