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Why are Chelsea so bad at defending set pieces, and what can we do to improve?

7+1 questions about Chelsea’s defensive woes from corners and free kicks

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The fact Chelsea are bad at set-pieces is not exactly a new discovery. It is a problem that has persisted since the beginning of the season and perhaps even last season. The only thing that has changed is the media attention it has received, with the goals conceded against Aston Villa and West Ham turning up the heat on head coach Frank Lampard.

Blame has been assigned to many culprits, including, but not limited to, Lampard, Kepa, and our central defenders. All of them are guilty to an extent.

The first step towards understanding the team’s set-piece problems is understanding the fact that there is no singular cause behind our ailments. The second step is to understand the fact our set-piece problems were not created overnight. Years of poor squad-building and negligence have led to this point.

Let’s take a look at Chelsea’s issues in the form of a few question and answers.

NB: The term “set-pieces” in this article refers to corners, indirect free kicks and throw-ins if applicable. Goals conceded from all these scenarios will be taken into account, instead of just goals conceded from corners. Goals conceded from direct free kicks have not been included.

NB: The term “aerial duels” refers to 50-50 duels in the air between two players. It does not include headers that were made uncontested, such a cross into the box being headed out by a defender with no opponent around him.

All data is valid as of Matchweek 33. The last Chelsea game taken into consideration was the 3-0 victory over Watford.


Question 1

Just how bad have Chelsea been at defending set-pieces this season?

Very bad.

In fact, Chelsea’s 12 set-piece goals conceded this season ranks them as the joint third-worst in the league. However you spin it, that is not good.

Question 2

Have set-pieces been a problem only this season or have they been a long-term issue?

While Chelsea have only received attention recently for their set-piece woes, it is far to say we have struggled with dead-ball situations for over 24 months now. Chelsea are conceding at a nearly identical rate of set-piece goals (around 0.36 per 90) this season as last season. That is, the team concede a set-piece goal almost every 3 games.

In terms of relative standing in the Premier League, Chelsea have been the joint third-worst both this season and last. For a club with aspirations to finish in the top-four, this is clearly a major weakness. The team have gradually transitioned from being one of the best teams in the league in terms of set-piece goals to one of the worst.

The increase in the number of set-piece goals allowed is backed up by underlying metrics as well. Chelsea have progressively allowed easier chances in set-pieces over the years, with the chances this season particularly unbecoming of a top club.

Interestingly, the quality of open-play chances has become easier over the years too, further emphasizing the point that our defensive woes were not created overnight and are the result of years of poor planning.

While not all solid set-piece teams end up winning the league, conceding double digit set-piece goals is definitely not the way forward. The worst set-piece team to have won the title in recent years was Leicester, who had conceded 8 on their way to beating 5000/1 odds.

Anything fewer than 8 set-piece goals over a season (roughly 0.21 set-piece goals conceded per game or a set-piece goal conceded every 5 games) can broadly be viewed as an acceptable figure.

Question 3

How much of this is down to the manager(s)?

While it is difficult to put a number on it, the managers will have to shoulder a portion of the blame. Firstly, let’s look at the systems used by Chelsea’s recent managers.

  • Frank Lampard: Initially zonal, now a hybrid system combining zonal and man marking.
  • Maurizio Sarri: A strict zonal marking system.
  • Antonio Conte: Man-marking except for players in the front post and goalmouth zones.
  • Jose Mourinho: A strict man-marking system.

There is no “good” or “bad” among these systems, that is something that must be understood. Each system carries has its pros and cons.

Let’s take a look at some of the goals conceded over the past two seasons to understand the systems of Lampard and Sarri.

Zonal marking:

Exhibit A: Richarlison’s goal in 2018-19.

Exhibit B: Victor Osimhen’s goal in 2019-20 and the defensive set-up leading up to the goal.

Both these examples involve lax marking and defenders losing the players in their respective zones. Lampard eventually moved to a more hybrid system, which appeared to have a brief positive impact before familiar weaknesses appeared again.

Zonal and man-marking hybrid system:

Exhibit C: Tomas Souček’s ruled out goal in 2019-20.

Exhibit D: Tomas Souček’s valid goal a few minutes later.

In the above two examples, Chelsea assign specific players to mark opponents and let certain players defend zones. However, in the case of the goal, there were several height mismatches that led to the ball ending up in the back of the net. César Azpilicueta was tasked with marking a player who was almost 6 inches taller than him and the result was fairly obvious. To do it once was bad enough, but two do it twice was bordering on ridiculous.

In the case of Souček’s ruled out goal, Chelsea also let the ball bounce in the box (something that the team have been guilty of doing on other occasions too) instead of clearing it. Chaos in the box then results in Kepa getting beaten, although VAR did save the team on this occasion.

In summary, zonal marking is a valuable tool to overcome lack of height in a team but is vulnerable to faster opponents crashing it and defenders ball-watching. Man-marking is good if there are solid, tall defenders capable of tracking players in the box.

The hybrid system used right now seems to be the correct solution in theory but there are significant flaws in how it is executed. Urgent changes are required.

Question 4

Are Lampard’s height concerns valid?

Yes, to an extent. Chelsea have become dramatically shorter over the past half-decade or so, going from one of the taller teams in the league to the opposite end of the spectrum.

While height does not necessarily translate to solid aerial ability (more on this later), having tall players is very useful for blocking off players making late runs across the box during set-piece routines, if nothing else.

While the absolute difference is relatively small, a fall by even a single centimeter in average height can have profound effect on the field. Strength, athleticism and the sheer ability to get in opponents’ faces used to set Chelsea apart from other top teams — this seems to have eroded gradually over the years.

In pursuit of playing “good” football, Chelsea appear to have forgotten what us one of the world’s best teams in the first place.

A quick look at the average heights of other title-winning teams shows that it is indeed possible to win using shorter players. However, there is a large caveat here. Most of Manchester City’s shorter players were attackers, meaning their lack of height was not going to majorly affect them under the right set-up.

When taking a look at the average heights of defensive players, a clearer picture emerges. City’s height in defensive zones is exactly what you would expect of most good teams. The current version of Chelsea fare poorly in this regard too. Chelsea have gone from having a squad of defensive behemoths to something far less impressive.

Chelsea’s current defensive corps are shorter by more than a centimeter when compared to the shortest title-winning defence in recent times, a very significant difference. Again, it must be noted that taller defences are not always better aerially but height’s importance cannot be discounted.

What caused this dramatic decline in height? A quick comparison in heights between title-winning players and some (not all) of their successors gives an idea.

  • Goalkeeper: Thibaut Courtois (1.99m) vs Kepa Arrizabalaga (1.86m).
  • Right back: Branislav Ivanović (1.85m) vs Victor Moses (1.77m) vs César Azpilicueta (1.78m).
  • Centre back: Gary Cahill (1.93m) vs Andreas Christensen (1.87m) vs Fikayo Tomori (1.85m).
  • Defensive midfield: Nemanja Matić (1.94m) vs Jorginho (1.80m).

These are just representative examples indicating the decrease in height and do not imply that any player is better or worse. The introduction of N’Golo Kanté (1.68m) has had an obvious effect too, although his skills elsewhere mean his lack of height is worth the trouble.

Question 5

How good are our centre backs aerially?

Well, “not great” is perhaps the right phrase. The last aerially dominant season from our centre backs was 2014-15, with subsequent seasons ranging from average to abject. It is rather surprising to see a defence with Rüdiger (1.90m), Zouma (1.90m) and Christensen (1.87m) struggle as much as they have aerially.

Please note that the rate in 2016-17 is influenced by the calculation of Azpilicueta (1.78m) as a centre back.

There is no clear link between title-winning pedigree and aerial proficiency judging by the past few seasons. Leicester seem to be the worst in pretty much every metric when compared to other title winners, as you expect from such a black swan event.

City’s decreased aerial proficiency in 2018-19, despite having a taller squad than the previous season, is notable. Liverpool are thoroughly dominant in the air, largely influenced by having Virgil Van Dijk in their ranks.

However, going by nothing but common sense, you’d rather be good in the air than not. Aerial duels here refers only to 50-50 duels in the air and not to uncontested headers.

Question 6

How much does the goalkeeper influence a team’s set-piece prowess?

A lot.

The influence of a goalkeeper is particularly profound when he is playing behind a defence without world-class defenders. As a Chelsea-related example, Thibaut Courtois was a major reason why the team had a terrific set-piece record in his time at the club. His ability to collect crosses played a significant role in relieving the pressure on his defenders and thereby elevated their confidence and performances.

Note how Ederson’s activity is higher in 2017-18, a season when Man City’s defence were shorter, when compared to 2018-19. Once his defence became taller, mainly through the introduction of world-class defender Aymeric Laporte (1.91m) and the return to fitness of the titanic Vincent Kompany (1.93m), Ederson’s cross collection decreased a notch simply because he wasn’t called upon as often. He was largely playing behind a defence of Nicolas Otamendi (1.83m) and the typically passive John Stones (1.88m) in 2017-18, meaning that he had to be more active in collecting crosses.

Once again, it must be emphasized that “aerial duels” only refers to 50-50 duels in the air and does not include uncontested headers made from crosses and such. This goes some way towards explaining why Ederson’s cross-collection load was lower in 2018-19 even though his defence had poor aerial duels stats that season.

At Liverpool, Alisson quite simply does not have to be active in collection crosses because he is playing behind the best defence in the league. Three of Liverpool’s centre-backs (Van Dijk, Lovren and Matip) are among the 15 best centre backs in the league in terms of aerial duels. Liverpool’s centre-backs are also supremely comfortable dealing with uncontested headers, which are not included in aerial duel stats.

Kepa in this regard is a bit disappointing. He is playing behind a defence that is not particularly good in dealing with 50-50 aerial duels (as backed up by stats) nor uncontested headers (as evidenced by the eye test), meaning he has to be more active in collecting crosses, just as Courtois once was. However, his indecisiveness in coming out is a contributing factor to Chelsea’s weakness against set-pieces and crosses in general.

Stats prior to the 2017-18 season for cross collection are unfortunately not available.

Question 7

Will signing a major centre-back automatically erase the team’s problems?

Yes and no.

Signing a world-class defender will obviously make the team better but not in the ways many would expect. Liverpool, for example. did not experience a drastic decrease in set-piece goals conceded immediately after signing Van Dijk, and instead had a more gradual route to success. However, there was a very clear decrease in the number of open play goals conceded and that is perhaps a better indicator of the effect Van Dijk had on the team.

Similarly, Liverpool also drastically improved in aerial duels after signing Van Dijk. They went from a team who were worse than Chelsea currently are, to one of the most aerially dominant teams in history. The improvement wasn’t overnight and instead followed a pattern of year-on-year improvement.

Looking at the average quality of chances conceded, it’s the same story. Liverpool started conceding chances that were less likely to become goals after the introduction of Van Dijk.

However, and it’s a big however, not all of this can be attributed to Van Dijk alone.

Signing one of the best centre-backs in Premier League history had a massive impact, undoubtedly, but just as important was Liverpool’s improved defensive organization, as elaborated upon in the next section.

The importance of Alisson cannot be underestimated either. Centre backs typically tend to perform better when they are playing in front of a goalkeeper whom they totally trust. Alisson’s presence has made some of Liverpool’s less heralded centre backs, such as Matip and Lovren, better just as much as Van Dijk’s aura has.


Question 8

(Non set-piece related)
FBL-ENG-PR-WEST HAM-CHELSEA Photo by MICHAEL REGAN/POOL/AFP via Getty Images

What can Lampard do to make Chelsea better as an overall defensive team besides improving set-piece defending?

Over the course of 2017-18 and beyond, Liverpool transitioned from a team that played to entertain to one that played to win. The role of increased pragmatism in Liverpool becoming a force cannot be understated.

Liverpool, like Chelsea at present, were once a team that focused on attacking non-stop and with as many players as possible. While this sounds appetizing, it also naturally leaves the team vulnerable at the other end, as has happened to us repeatedly.

FBL-ENG-PR-EVERTON-LIVERPOOL Photo by JON SUPER/POOL/AFP via Getty Images

Eventually, Liverpool moved to a system which allowed four players behind the ball on most occasions — the two centre backs and two of the three central midfielders — which made them far more secure defensively. This involved toning down their pressing, too, leading to a more measured approach.

This meant Liverpool weren’t as “sexy” as they once were going forward but the trade-off between the praise of neutrals and 3 points every week has been certainly worth it.

Manchester City broadly adopted the same process too. From a cavalier team in 2016-17, they eventually settled on having four men behind the ball as well. In City’s case, it was the two centre backs, plus Fernandinho and one of the full backs.

They still continued scoring bucket-loads of goals because of the sheer depth, variety and quality of their attacking options. If anything, having four men behind the ball made their jobs easier by making the attacking zones less congested.

Manchester City v Liverpool FC - Premier League Photo by Peter Powell/Pool via Getty Images

Judging by rumoured targets such as Kai Havertz, Chelsea seem more suited to following City’s route to defensive solidity than Liverpool’s. This means keeping the deepest midfielder as nothing but a screening option off the ball (meaning he will not charge forward to press) and not committing both full backs at once.

City became far more solid once they signed Ederson, a goalkeeper whom the team trusted, too. A team not confident in their goalkeeper will never challenge for major honors.

There is clear precedent for Lampard to follow if he wants Chelsea to become more solid defensively. The pertinent question is, will he follow the precedent?


Conclusion

Chelsea’s set-piece problems have been a long time coming. They weren’t created overnight and are instead the result of years of poor squad planning and ignoring the traits that made this club (and others) successful.

Lampard changing his tactics alone won’t improve the team. Chelsea buying a new goalkeeper alone won’t improve the team. Chelsea buying good centre backs alone won’t improve the team. However, doing all of them will lead to positive results and Chelsea returning to where we truly belong.

In short, this is not a Lampard problem. This is not a Kepa problem. This is not a Rüdiger problem. This is a Chelsea problem. Thanks for reading.

Huddersfield Town v Chelsea - Premier League Photo by Simon Stacpoole/Offside/Getty Images
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