Real Madrid and Atletico Madrid played out a 1-1 draw at the Bernabeu which featured a controversial penalty decision against the hosts.
After a week in which Madrid protested against referees -- with Atletico mocking their rivals on social media -- referee Cesar Soto Grado judged that Aurelien Tchouameni had stepped on Samuel Lino in the penalty area in the 35th minute, much to the bemusement of the home side.
Julian Alvarez nervelessly converted from the spot but Real Madrid came back into the match after half-time.
Kylian Mbappe turned home a loose ball in the 50th minute to draw the sides level and Madrid pushed forward, but they could not find a winner against their city rivals. The result means Madrid are still top of La Liga, one point ahead of Atletico.
Here, our writers break down the key talking points.
A slow-burning game came to the boil just past the half-hour mark when Atletico winger Lino went down in the box under a challenge from Madrid's stand-in centre-back Tchouameni.
Play continued and most in the stadium followed the ball, but Lino stayed down and eventually VAR official Ricardo De Burgos Bengotextea called the attention of referee Cesar Soto Grado.
There was now huge noise inside the stadium as fans watched replays of the incident on the Bernabeu's huge new overhead screens. Madrid boss Carlo Ancelotti had his head in his hands, while Simeone argued with the fourth official.
When Soto Grado pointed to the spot, there were loud chants of "Corruption in the federation" from the semi-official supporters' stand behind Thibaut Courtois' goal. Amid all the furore, Atletico forward Alvarez showed remarkable composure to keep his head and nonchalantly convert from the spot.
It was the first penalty whistled against Madrid in La Liga in almost a year, and was a call which could be argued either way, but most fans at the Bernabeu were outraged.
This was never going to be a straightforward game for Soto Grado after a week in which Madrid had attacked the refereeing system in Spain, with its Real Madrid TV channel highlighting past decisions both he and De Burgos Bengotextea had made that went against their team.
Madrid fans had also complained earlier in the game when midfielder Dani Ceballos was booked for a challenge on Atletico's Pablo Barrios, in another incident many in the stadium missed at the time. In this case the replays were more conclusive and Ceballos deserved at least a yellow for the foul.
Dermot Corrigan
When Alvarez decided to leave Manchester City for Atletico last summer, it was to play a prominent role in games just such as this.
Alvarez grew frustrated during his time at City at not being involved in the biggest games. He was given just three minutes off the bench during two Champions League visits to the Bernabeu during his time with the Premier League side.
The Argentine wanted the spotlight on him, and it clearly was when Atletico were awarded their controversial penalty just past the hour mark.
The noise was overwhelming inside the stadium, the fans behind the goal were doing their utmost to put Alvarez off, and the pressure was huge given the stakes in the La Liga title race.
After the ball was placed on the spot, Courtois tried to distract Alvarez by waving his right hand at him but the striker kept his eyes focused on the referee until he had to strike the ball.
When the whistle blew, he kept his head down and kept complete control of the situation -- lifting a delicate finish into the net as Courtois dived away to the left.
Alvarez was then engulfed by celebrating teammates as Madrid kept complaining to the referee. It was a fantastic moment for Atletico's new star -- and further confirmation the difficult decision he made to leave City last summer is paying off.
Dermot Corrigan
Atletico's out-of-possession structure was always going to pose problems for Madrid's front four -- Vinicius Junior, Mbappe, Rodrygo and Jude Bellingham.
Simeone opted for his routine 4-4-2 shape, which cut out any spaces in the middle and required the hosts to work their way around the Atletico shape. For much of the opening half hour, Madrid could not do so.
That in turn led to all of Madrid's front four taking turns to drop into midfield and try to work their way past their opponents using one-two passing moves, but they were sloppy with the ball. Bellingham lost possession 10 times, his joint third-worst figure in the first half of a league game this season. Rodrygo lost the ball seven times too.
That left full-backs Fran Garcia and Lucas Vazquez to provide the width but neither was quick enough to trouble Atletico, who doubled up on the Madrid full-backs to force them backwards. As the graphic below shows, nearly half of Madrid's attacking touches in the first half came on the right flank but resulted in no clear-cut opportunities.
It also led to moments like the one below, with all of Madrid's forwards camped in the centre of the area rather than using their pace to beat Atletico out wide.
That changed considerably in the second half, with Rodrygo manning the right wing and Vinicius Jr stretching Atletico's backline by staying wide on the left when Madrid had possession, while Mbappe stayed central and Bellingham made the runs from midfield he excels at. That helped lead to the equaliser, as Rodrygo cut the ball back for Bellingham, whose shot was blocked before Mbappe converted, with Atletico also having to focus on Vinicius Jr at the far-post.
That goal led to more fluidity too. With Rodrygo continuing to stay wide on the right, Mbappe and Vinicius Jr exchanged positions better, while another Bellingham run from midfield led to a headed opportunity that Jan Oblak saved shortly after the goal.
Vinicius Jr had a lot more joy down the left too, driving and forcing mistakes from Atletico's tiring defence, with Marcos Llorente struggling to keep up with the Brazil forward. It helped unsettle the visitors' backline and get the Bernabeu going as Madrid pushed for a winner.
Anantaajith Raghuraman
This was not a classic Derbi Madrileno -- the game had more moments of controversy than true quality -- but it does leave things nicely set up for what could be a hugely exciting three-way La Liga title race, with no clear favourite at this point.
Madrid had lots more possession and shots on goal over the 90 minutes, although Atletico could also claim they had their opportunities to pull off a rare win at the Bernabeu.
After Mbappe's equaliser, Madrid looked to have Atletico on the ropes. They were left to rue Bellingham's header from inside the six yard box cannoning back off the crossbar during a period in which Simeone's side were barely able to get out of their half.
Mbappe and Vinicius Jr were also denied by Atletico keeper Oblak later in the second half, and Rodrygo fired just wide from 20 yards. In the 89th minute, Mbappe was through again, but he was denied once more by Oblak.
So this was yet another game this season against a big team in which Madrid were not able to emerge with a victory.
It was a second draw between the two city rivals this season. In the first game in September at Atletico's Metropolitano, Madrid were ahead going into added time before Angel Correa's equaliser.
That means Ancelotti's team have had chances to put a clear gap between them and their neighbours during those two games but have not been able to.
The draw put Madrid onto 50 points, with Atletico on 49. Third-placed Barcelona can reach 48 if they win at out-of-form Sevilla on Sunday.
All three teams are also into the Copa del Rey semi-finals and the latter stages of the Champions League -- meaning the games for all three are coming thick and fast.
A more decisive Madrid team tonight might have made a real decisive step with a victory to take control of the title race. But Atletico hung in there, and look set to stay involved at the top right towards the end of the campaign.
Dermot Corrigan
We will bring you this after he has spoken at the post-match press conference.
Tuesday, February 11 Manchester City (Away); Champions League play-off, first leg; 8pm GMT, 3pm ET