Two of the best teams in LaLiga coming face to face at this stage of Europe's most glamorous club competition is further indication that football in the region is still in rude health.
Los Blancos had won two of the last six Champions League titles, though there had certainly been a shift since Real's 2017/18 triumph over Liverpool - the fifth UCL winners in succession to come from Spain at that point.
Carlo Ancelotti's side also had something else to celebrate at the Santiago Bernabeu when they walked out to a cacophony of noise and one of the biggest tifos that the famous old ground has ever seen.
It was the host's 500th match in the European Cup/Champions League, making them the first team in the history of the competition to reach this milestone. Prior to Tuesday's match, Real had won 301 games in the competition (including qualifiers), drawn 85 and lost 113.
On a more recent note, the all whites had only lost one of their last 17 matches in the UCL knockout stages (winning 11 and drawing five), and were unbeaten in nine (winning five and drawing four).
Their only defeat in this particular run came away to Manchester City in the 2022/23 semi-finals when they were battered 4-0 on a night to forget, Pep Guardiola's swashbucklers famously going on to win the treble, of course.
Against Atleti, things got off to a brilliant start for the home side with Rodrygo's opener being the earliest goal scored in a Champions League knockout game since Cristiano Ronaldo's 3rd minute strike (for Real) against Juventus in the quarter final in April 2018.
Julian Alvarez had the Rojiblancos back in business with a sensational strike before the break, but it was Brahim Diaz who was to have the final word, giving Los Blancos a 2-1 win and the slenderest of leads to take back across the Spanish capital for the second leg.
His goal, when it arrived, was a thing of beauty, crafted as it was from back to front, from Thibaut Courtois forward, and including 20+ passes.
The quality of his finish shouldn't be understated either.
Involved on more than one occasion in the build up, Diaz's quick feet bamboozled Giuliano Simeone and Jose Maria Gimenez, though he still had Pablo Barrios, Marcos Llorente and Clement Lenglet in his direct sight line as he addressed the ball, ready to pull the trigger.
Were it not for Lenglet's very slight movement to his left, which opened up a small channel for Diaz to slot the ball through, the chance would've been gone.
It still required speed of thought and accuracy from the Real Madrid man's point of view, however, and finding the net directly inside the far post was just about the only place he could aim for and be assured that Jan Oblak wouldn't be able to get to the ball.
It was his second goal in this season's competition, the other coming against Manchester City in February, but it's his all-round performance that should have everyone sitting up and taking notice.
For a start, three successful tackles from three made was the most of any Real player against Atleti, and given that the Rojiblancos are always considered as the more dogged of the Madrid sides, only Pablo Barrios and Jose Gimenez managed to match Diaz in terms of tackles made.
That 'bite' might sometimes be considered necessary for a Real team that is more renowned for their attacking intent than their ability to put their foot in when needed.
Indeed, it's the tigerish nature to Diaz's game which sets him apart - in a good way. Without wishing to do the player a disservice, he is more a work horse than a thoroughbred, but his willingness to push through brick walls for his team is clearly appreciated, and arguably needed in certain games. It also indicates why Carlo Ancelotti was right to put him in the starting XI against Atleti.
Six ball recoveries against them was also his joint best of the 24/25 Champions League campaign, Liverpool being the other opponents against whom he excelled in this regard, even if Los Blancos were beaten 2-0 on that occasion.
His 12 duels (vs Atleti) was a season high for him in the competition, with such output perhaps to be expected against the toughest of domestic and, on this occasion, European opponents. It was the most from a Real player in the game, but he'll almost certainly be disappointed with only winning half of those, even if that was also a joint match high with Vinicius Jr. (six from 11 duels).
On the only other occasion this season where he was also involved in 12 UCL duels - in the 3-2 league stage win in Atalanta, Diaz was much more bullish winning the ball nine times.
Against Diego Simeone's side he managed to complete 50 of his 53 passes for a magnificent pass success rate of 94.1%.
As if to further evidence how busy Diaz made himself on Tuesday, his five touches in the opposition box were the most of any player on the pitch with the exception of Kylian Mbappe, also with five.
One successfully completed dribble was as good as any of his teammates, and only three Real players had more than his 76 total touches in the game, two of whom were defenders (Valverde, Mendy).
From a personal perspective, Diaz should therefore feel rightly proud of his match-winning contribution, and he'll almost certainly have given Carlo Ancelotti some more food for thought ahead of the second leg.
