Right-back: Juanfran (Sao Paolo)
Originally a winger, Juanfran turned into an accomplished full-back at Atletico Madrid, featuring regularly for the side for nine years after arriving from Osasuna in 2010. While his numbers weren't extraordinary, the Spaniard's defensive work was top notch.
In 2016, ESPN FC ranked him as the third-best full-back in the world. Even though one of his more enduring memories with Atletico Madrid is a penalty miss in the Champions League final that year, Juanfran is widely hailed as one of the best in the club's history.
With 355 appearances, 41 assists and seven trophies under his belt, Juanfran moved to Brazil to join Sao Paolo in 2019 after the end of his contract with Atletico Madrid.
Centre-back: Diego Godin (Cagliari)
Another club legend, Diego Godin was an unbreachable bulwark that gave even the world's mightiest strikers a serious run for their money. He was also a key cornerstone in Atletico Madrid's first revolution under Simeone.
Despite lacking in pace and athleticism, the Uruguayan made a difference with his excellent positioning, superb organisational skills and exemplary leadership qualities. He guided his side to eight titles, including the historic La Liga title in 2014, when he scored the decisive goal on the final day of the season against Barcelona.
After his contract expired in 2019, Godin joined Inter Milan, ending his Atletico Madrid career with 389 caps. He's presently representing another Serie A side, Cagliari, after leaving Inter this summer.
Centre-back: Toby Alderweireld (Tottenham Hotspur)
Toby Alderweireld is somewhat of a forgotten man at the Wanda Metropolitano. He appeared only 12 times for the club during the 2013-14 season, but the Belgian merits a spot here for the stature he commands today.
After coming through the ranks at Ajax during his six-year spell in Amsterdam, the centre-back struggled to force his way into the Atletico Madrid starting-XI as Godin and Jose Gimenez held an iron-grip at the heart of the backline.
After a successful loan spell with Southampton the next season, Alderweireld joined Tottenham Hotspur permanently in 2015 and has since established himself as a top defender in the Premier League. He even won the club's Player of the Year award in his debut season.
Left-back: Theo Hernandez (AC Milan)
This was a hard choice between the Hernandez brothers, Lucas and Theo, as both came through Atletico Madrid's ranks. While Lucas played for the side for five years, he wasn't a first-teamer; Theo never played for the Atletico Madrid senior team but is now fast developing into a world-class full-back.
That's exactly why we've chosen to go with Theo here, as his performances with AC Milan since joining the side last season may have left the Madrid side wondering if they let the wrong Hernandez go.
Theo Hernandez even struggled to establish himself with Atletico Madrid's crosstown rivals Real Madrid in the 2017-18 season but has come of age in the Serie A. He contributed 11 goals last season and brought about a new dimension to the Rossoneri attack with his prolific dribbling skills and crossing ability.