Atlético Madrid edged the capital derby against Real Madrid 2-1. The contest began evenly before the hosts took control after Dean Huijsen's sending-off early in the second half, a moment that reshaped everything and handed Diego Simeone's side a precious win that leaves Real Madrid six points behind league leaders Barcelona.
Refereeing controversy raged throughout. Real Madrid protested the failure to show a red card in more than one first-half incident, most notably Cuti Romero's challenge on Jude Bellingham, along with Kang-in Lee's challenge on Federico Valverde.
Real Madrid's channel argued both players deserved to be sent off, which would have forced Atlético to finish with nine men, before the matter ended with Huijsen's dismissal in the second half after a VAR intervention.
Both sides knew the margin for error had become razor-thin given Barcelona's perfect start, and so the opening minutes were cautious and tense, with no clear attacking thrust from either side.
The win left Real Madrid on 15 points, six behind Barcelona, while Atlético climbed to 16.
Simeone set up in a 3-4-2-1. Real Madrid countered with a 4-2-3-1, fielding Arda Güler, Jude Bellingham, Vinícius and Kylian Mbappé in the front line.
Despite Atlético's edge in possession, control never translated into real danger, while Real Madrid relied more on transitions and attempts to exploit space.
Mbappé summed up that picture. He stayed far from influential throughout the first half, touching the ball only 23 times and losing it on eight occasions without managing a shot on Jan Oblak's goal.
Real Madrid's most dangerous moment fell to Arda Güler, who tested Oblak with a long-range effort in the 41st minute. The goalkeeper kept it out, and the first half ended goalless despite Atlético holding 55% of the ball.
The balance did not last long after the break. From the opening minutes of the second half, the match began to shift clearly.
Courtois saved a shot from Baena, then came the decisive moment. Giuliano Simeone went down inside the penalty area following a challenge from Dean Huijsen.
The referee pointed to the spot. Video technology then reviewed the incident before the decision turned into a red card for Huijsen, completely changing the calculations of the match.
Now Real Madrid had to face Atlético for the greater part of the second half with 10 men, handing the hosts a numerical advantage and more room to move.
Grimaldo took the penalty and Courtois saved it, but Atlético pounced on the follow-up to go ahead.
This was not merely a lead on the scoreboard. It arrived at a moment when Real Madrid had to attack despite being a man down, which gave Atlético even more space to break forward.
Just eight minutes later, Atlético exploited that advantage and doubled their lead through Jonathan David, an organised attack finished off after a pass from Giuliano Simeone. Real Madrid's task grew harder still, especially as they had not shown enough attacking ability to threaten Oblak consistently.
Mourinho tried to change things from the bench, but the substitutions could not shift the attacking picture enough.
Bellingham and Mbappé stayed quiet as Atlético grew more comfortable, managing the game and milking their numerical superiority and their lead.
Courtois kept Real Madrid alive at the other end. He saved a header from Cuti Romero, and the defence then blocked another Atlético attempt.
In the 79th minute, Yan Diomande wasted a chance to extend the lead after going one-on-one with Oblak, but the goalkeeper stopped his shot.
Hope flickered late on. Antonio Rüdiger pulled one back in the 89th minute, rising to meet a Bernardo Silva free-kick and burying it. The goal restored tension to the closing minutes, with Real Madrid throwing everyone forward in search of an equaliser.
Atlético withstood the final pressure and held on until the whistle, repeating their dominance over Real Madrid on home soil and leaving the derby with three points that strengthen their grip on second place.