Despite being popular in Italy for a while now, the use of three rather than two central defenders is slowly making its way across the entire continent. With such a large group of teams now adopting the 3-4-2-1 formation, it's time to assess who has done it the best over the course of the campaign. The stats are in from Squawka, so let's take a look at which back three have come out on top this season. Back three: Federico Fazio, Antonio Rudider and Kostas Manolas Statistically the tightest...
Back three: Sokratis Papastathopoulos, Marc Bartra and Lukasz Piszczek
BVB manager Thomas Tuchel only used a back three on 15 occasions this season, but with just 20 goals conceded during that period it's enough for them to make the list. It's been an indifferent season for the Bundesliga, but beating Bayern in the DFB Pokal semi final will make up for their shoddy league displays.
Average goals conceded per game: 1.33
Back three: Jesus Vallejo, David Abraham and Makoto Hasebe
The team that Dortmund will be meeting in the domestic final is Eintracht Frankfurt, who themselves have also utilised a back three at times this season. The multicultural trio of a Spaniard, Argentinian and Japanese at the back for Die Adler has worked well, although they remain midtable in Germany.
Average goals conceded per game: 1.29
Back three: Mattia Caldara, Andrea Masiello and Rafael Toloi
The surprise package of the Serie A this season, Atalanta look set for automatic qualification to next year's Europa League. One reason for their success has been a solid back line, which has been marshalled by Italian duo Caldara and Masiello, and Brazilian Toloi, the three of whom have played together 30 times for La Dea.
Average goals conceded per game: 1.1
Back three: Kevin Vogt, Niklas Sule and Benjamin Hubner
Yet another Bundesliga side in the top 10, Hoffenheim looked at one point as if they might even challenge for the title and their win at 1-0 home to Bayern illustrated their defensive stability. 21-year-old German international Niklas Sule has been particularly impressive this term, so much so that Bayern have already secured his signature for next season.
Average goals conceded per game: 1.08
Back three: Malang Sarr, Paul Baysse and Dante
No one would have expected Nice to have done as well as they have done this year, with Luicen Favre's men all but confirmed for a Champions League finish. A back three has been a rare commodity this season, just 10 times, but when used it's worked wonders. Former Bundesliga star Dante has combined especially well with one of Europe's best prospects, under 18 French international captain Malang Sarr.
Average goals conceded per game: 1
Back three: Naldo, Benedikt Howedes and Matija Nastasic
What a trio these three are. Schalke stalwart and German World Cup winning defender Benedikt Howedes has, at times this season, dropped to the back line alongside Nastasic and Naldo in order to shore up proceedings. Again proving that Bundesliga sides have used this formation well, the Gelsenkirchen club have had a disappointing campaign, but, as a back three, it's been a grand success.
Average goals conceded per game: 1
Back three: Leonardo Bonucci, Giorgio Chiellini and Andrea Barzagli
One of the original proprietors of the back three, Juventus boss Massimiliano Allegri has actually converted to a traditional back four in recent months with Barzagli dropping to the bench. Nonetheless, in the 13 games that the Italian trio have played together it was business as usual, with only 12 goals conceded.
Average goals conceded per game: 0.92
Back three: Toby Alderweireld, Jan Vertonghen and Eric Dier
Spurs manager Mauricio Pochettino has varied with his preferred formation, with the versatility of Eric Dier allowing him to drop back into a back three when needed. The Belgian duo of Toby Alderweireld and Jan Vertonghen are arguably the best defensive pairing in the Premier League, with the North London club conceding the least amount of goals this season.
Average goals conceded per game: 0.7
Back three: David Luiz, Cesar Azpilicueta and Gary Cahill
Unlike title rivals Spurs, Chelsea have been consistently using the 3-4-2-1 formation, with Italian boss Antonio Conte introducing it shortly after the season started. The change has allowed the Blues to emerge as strong favourites to claim the title, with David Luiz's return last summer a key element as the central figure in the back line.
Average goals conceded per game: 0.69
Back three: Federico Fazio, Antonio Rudider and Kostas Manolas
Statistically the tightest back three in Europe this season, Roma have somehow turned the career of Federico Fazio around, following his nightmare stint with Spurs. The giant Argentinian has combined perfectly with Greek international Manolas and German defender Rudiger to provide the Italian side with a solid base.
Average goals conceded per game: 0.58