With 24 games played in La Liga, Atletico Madrid have let in just nine goals this season. They are the only club in Europe's top five leagues (Premier League, La Liga, Bundesliga, Serie A, Ligue 1), who have conceded fewer than ten goals, making Jan Oblak the clear favourite for the Zamora award (the Spanish version of the Golden Glove).
When it comes to the defence, their only rival is Barcelona. Ernesto Valverde's side have only let in eleven goals during this season's league campaign, thanks in part to Ter Stegen's impressive form. That being said, Barca can't compete with Simeone, who has proven himself to be the master of setting up a defence.
Next in the list are two Italian teams: Juventus and Napoli. The two Serie A title challengers have let in 15 goals apiece, with the two sides' impressive back lines allowing them to maintain their excellent form as they continue the fierce battle for the league.
In the Bundesliga, Bayern Munich have conceded just 19, putting them equal with both Paris Saint-Germain and Manchester United in terms of defence. PSG and Bayern are both top of their respective leagues, but United are trailing their rivals Manchester City (who have let in 20 league goals) by 16 points.
So, Atletico Madrid have without a doubt the strongest defense in Europe, and Simeone's side will hope to continue this solidarity as they challenge for the Europa League and attempt to catch Barca in La Liga.