Madrid - Often overshadowed by the glitz and glamour of Real Madrid's galacticos and collective brilliance of Barcelona's attacking triumvirate of Lionel Messi, Luis Suarez and Neymar, Atletico Madrid have carved out their own golden era on a historically great defence.
PSV Eindhoven travel to the Vicente Calderon for the second-leg of their Champions League last-16 clash on Tuesday, with the tie finely balanced at 0-0, tasked with one of the most difficult challenges in European football: breaching the Atletico backline.
In 14 Champions League matches at home since Diego Simeone rode to Atletico's rescue four years ago, only three sides have managed to score with Benfica, earlier this season, the only away team to win in the Spanish capital.
Quiet but efficient, Atletico's defensive numbers this season are on course to be the best of all time.
With a remarkable 27 clean sheets in 42 games in all competitions, goalkeeper Jan Oblak is set to break Paco Liano's Spanish record of 18 for the fewest number of goals conceded in a La Liga season.
Oblak has been beaten just 12 times in 29 Liga games so far, four of which came in two games against Messi, Suarez and Neymar.
Thanks to Real Madrid's administrative tardiness in trying to land David de Gea last August, Oblak remains the most expensive goalkeeper in Spanish football history after his 16 million euro ($17.8 million) switch from Benfica in 2014.
Yet, faced with the daunting task of replacing Thibaut Courtois, Oblak had a difficult start to life at the Calderon.
He initially lost out to Miguel Angel Moya in the battle to be Simeone's first choice and it wasn't till this stage of last season's Champions League that he began to prove his worth.
Brought on to replace the injured Moya, Oblak kept a clean sheet and saved a penalty as Atletico progressed in a shootout against Bayer Leverkusen.
"I always laud the work, commitment and, above all, the way in which he won his place," Simeone said of the Slovenian.
"He waited for his moment, worked hard and when someone works the rewards come.
"He has an enormous future. We hope he doesn't stop improving."
Atletico were so keen to make sure Oblak is part of their promising future they gave him a major pay rise and extended his contract to 2021 last month.
Yet, Oblak is far from the only rock in Atletico's defensive wall.
Having seen Radamel Falcao, Diego Costa and Arda Turan sold in recent years, the one player Simeone has insisted he'll never let go is Uruguayan braveheart Diego Godin.
The return of left-back Filipe Luis after a year at Chelsea has reunited three-quarters of the defence that won Atletico the La Liga title and went within a minute of winning the Champions League in 2013/14.
Juanfran has been installed as Spain's first-choice right-back, whilst, at just 21, Jose Maria Gimenez is already one of the world's best centre-backs.
More than names, though, it is Simeone's relentless insistence on hard work and organisation that makes Atletico so hard to breakdown.
"Simeone is the stone around which this project is constructed," said Godin.
"He has strengthened this group of players. He has made the players and fans believe, not just with words but with acts."
In four years under Simeone, Atletico have won a trophy every season. After the Europa League, UEFA Super Cup, Copa del Rey, La Liga and Spanish Super Cup, only one piece of silverware has eluded the Argentine: the Champions League.
Coming so close before losing out in heartbreaking fashion to Real Madrid in the final two years ago has only hardened Simeone's desire to deliver Europe's premier title to the Calderon for the first time.
The next step is seeing off PSV to reach the last eight for the third consecutive season.
Having constructed steely foundations, Atletico believe their time is coming.