Since 2014, Atletico Madrid have consistently registered brilliant defensive numbers.
There are a myriad of reasons for this. For one, Diego Simeone - the cult of personality at the head of Atleti's modern revival - has bred a very specific footballing philosophy in the Spanish capital over the past decade.
Derided by purists as being anti-football and heralded by pragmatists as edgy antiheroes, Simeone's sides have consistently been nigh-on impossible to break down. Shaping up in two compact banks of four when out of possession, Atleti's tireless work rate and freakish discipline make them a nightmare to play against. Many giants have been slain at home and abroad, after being tactically outclassed by Simeone.
Then there's the individual quality of their back four. During this period, the likes of Diego Godin, José Gimenez and Stefan Savic have performed super human defensive feats - and that's just a few of the centre backs who have passed through Wanda Metropolitano.
Above all else though, the key figure in Atleti's stingy defensive record is a lanky 27-year-old from the tiny Slovenian town of Škofja Loka.
Jan Oblak arrived at the club in 2014 with big shoes - or gloves - to fill. Thibaut Courtois had just returned to Chelsea after what was probably the most successful loan move of all time. The big Belgian helped Simeone's side reach two Champions League finals and seal an impossible La Liga title the previous season.
Oblak was more than up for the task though, usurping Miguel Angel Moya as Atleti's number one halfway through his debut campaign and never looking back. The €16m the club paid Benfica for his services has proved to be an incredibly shrewd piece of business, especially in a transfer market in which Kepa Arrizabalaga's poppadom wrists cost four times that.
The remarkable consistency displayed by the Slovenian makes it challenging to pinpoint the exact moment when he became the best goalkeeper in the world.
After cementing his place as Simoene's number one goalkeeper, Oblak's first full season in the Spanish capital was phenomenal. He did not miss a single second of La Liga action, conceding just 18 - yes, 18 goals - and keeping 24 clean sheets. Unsurprisingly, the former remains a joint league record.
Oblak has maintained a similar level of stinginess in subsequent seasons. The highest amount of goals he has ever conceded in a domestic campaign for Los Rojiblancos is 27, which he has done on two occasions. Even in these fallow years, Atleti still comfortably finished in the top three with Oblak one of their top performers. His save percentage has never dipped below 0.750 throughout his time in Madrid as well. A truly incredible feat.
These records say a lot about Oblak as a player. While many modern keepers are more adept with their feet than their hands, the Atleti stopper's approach is a refreshing throwback. He is a traditional goalkeeper whose singular purpose is stopping the ball hitting the back of the net by any means necessary.
There's no danger of Oblak being described as a 'sweeper keeper' as he has consistently registered one of the lowest average distances away from his goal when performing defensive actions in La Liga. His distribution skills may also be lacking by modern standards - but these skills are not required in Simeone's system. It's a match made in heaven.
Despite all the evidence being there for years it has only been in the past two seasons or so that Oblak has begun to be perceived as the world's best. A lot of this has to do with the regression of some of his rivals, with David de Gea and Manuel Neuer both shadows of their former glorious selves.
A string of statement performances in high profile fixtures have also helped Oblak's cause, none more so than his heroic display against Liverpool back in March.
The last properly big game before COVID-19 brought football to a grinding halt around the world, the Reds went into the second leg of this Champions League round of 16 tie 1-0 down. A quick glance at the stats without knowing the final scoreline would seem to suggest that Jurgen Klopp's title winners got the job done as well.
Liverpool enjoyed 71% possession, had 34 shots on goal and had an xG of just under three. However, the Reds didn't account for Oblak putting in one of the great all-time European goalkeeping performances.
The Slovenian made nine saves in the contest. Some of them were beautiful. A finger tip stop to keep out Alex Oxlade-Chamberlain's low drive and a point blanc block to deny Roberto Firmino were particular highlights as Oblak provided the platform for his side's dramatic 3-2 victory at Anfield.
It's something he's done many times before. With Oblak between the sticks - by far the best goalkeeper on the planet - what's to stop Atleti ending their Champions League hoodoo this time around?