Chelsea’s Almost Impeccable Defence

Chelsea are on top of the table, and a lot of Chelsea’s success should be attributed to Antonio Conte, for his 3-4-3 formation, which has started a trend in the Premier League. With the most goals in the league and the third-lowest goals conceded, even the most pessimistic Chelsea fan is certain that Chelsea will lift the Premier League title.

Their attack, however, is surfing a wave of variance. According to the xG data on Benjamin Pugsley’s fantastic website Objective Football, Chelsea has scored around 21 more goals than expected, and has put up only the 5th highest xG in the Premier League. Their defence has been the real reason for their league performance, as most of their attacks spring from fast breaks. With the third lowest xG conceded in the league, and still underperforming actual goals, what is Chelsea doing that makes them so good at the back?

The Shooting

The locations of the shots Chelsea conceded (left) aren’t too different from the shot locations of Tottenham (right).

Untitled.png

However, Chelsea commit more players behind the ball before a shot. According to Stratagem, Chelsea on average keep 2.85 players between the goal and the ball per shot, while Spurs keep 2.34 players. That doesn’t seem like a huge difference, but it is telling when you compare it with the rest of the league.

Defensive Pressure and Defensive Players.png

Chelsea is the hardly visible yellow dot in the middle, so they’re like the average Premier League side for defensive pressure and defensive players per shot conceded.

Chelsea don’t defend by keeping the ball. With 53.6% of possession (but then again, are we really calculating possession correctly?), they are 6th in the league in terms of keeping the ball.

Pressing

Chelsea definitely don’t press high. In terms of PPDA and pass completion against, they use a low block, like Chelsea’s side under Mourinho. For PPDA, I used passes against and defensive actions for the entire pitch, as I can’t figure out how to use a scraper.

PPDA and Pass Prevention % in the PL

Different teams use pressing in different parts of the field. Chelsea don’t press very high, as they don’t stop many passes in the opposition’s defensive third. As you can see in the following graph, Chelsea are, in fact, sub-par at this.

Pass Prevention % in the Final Third.png

They don’t press the opposition near the middle of the pitch, either. Some bottom-table teams are better at pressing in the middle third of the pitch than Chelsea.

Pass Prevention in the Middle Third.png

Chelsea are slightly better at intercepting passes in their own defensive third, although the rest of the top six and Southampton allow less passes in their own third.

Pass Prevention % in Own Third.png

Chelsea’s low block is quite brilliant. Chelsea’s players don’t attempt tackles too many times (8.4 per game, 18th in the league), but don’t get dribbled past a lot (8 per game, best in the league), and focus on getting the ball back through interceptions (19.2 per game, 9th in the league).

Teams have to work very hard before penetrating Chelsea’s defense and shooting, as Chelsea concedes very less xG, even though the opponents pass the ball around a lot against them.

xG Conceded by Passes Against.png

Chelsea don’t let their opponents spend time in Chelsea’s own defensive third, as they have a healthy field tilt (opponent defensive third passes/opponent final third passes). They let the game come to their own area, and win the ball back there.

Field Tilt in the PL.png

With a fairly compact defence and ball-oriented movements, Chelsea’s defensive system is excellent. When the ball gets into the final third, the wing-backs and defensive midfielders start to use an option-oriented zonal marking system in a five-chain at the back (I know, I’ve read way too much Spielverlagerung).

Chelsea Defensive Shape.png

The Players

The public has credited the marvelous N’Golo Kanté and David Luiz for their performances, but in fact all of Chelsea’s defensive minded players have been impressive this season. They all have different roles while defending. Kanté acts as a hunter, charging and moving with the man in possession. Nemanja Matic balances this out by sticking to his position and providing stability. David Luiz and Gary Cahill are passive defenders, while Cesar ‘Dave’ Azpilicueta is active, and looks to win the ball back and move forward with his excellent ball-playing skills. The wing-backs have similar roles.

Chelsea's Defensive Players Compared.png

As you can see, the data backs this up. Chelsea’s goalkeeper Thibaut Courtois isn’t the reason for Chelsea’s lack of goals conceded, as shown by Paul Riley.

Chelsea’s shape and crunching of space is why Chelsea has maintained a low xG conceded total, and Thibaut Courtois is why Chelsea are still underperforming xG in defence. Not that this is anything to worry about for Antonio Conte. They have seven great players in front of Courtois.

Conclusion

I’m not quite sure if Chelsea deserve to win the Premier League this year, with the other teams performing marginally better, especially Tottenham and Manchester City. They haven’t been a great attacking threat and have been playing the same steely, defensive, counter-attacking football they are famous for playing. But this is why Chelsea’s boardroom made such a good decision in hiring Antonio Conte as manager, and buying players like David Luiz, N’Golo Kanté, and Marcos Alonso. Chelsea. With talented players like these and a great manager, Chelsea is a force to be reckoned with. Even if that means they don’t look good while being the champions of England. Let’s hope they win another ten titles.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.

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