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Introducing xA HeatMaps: How Mumbai City FC fared in Attack and Defence in ISL 6

How Mumbai City FC fared in Attack and Defence in ISL 6
Picture Credit: Mumbai City FC

READY RECKONER

As the coaching and tactical nous rises in Indian football, it is only fair that the stats community follows suit.

Having created a prototype of xA Heatmaps for Indian football, we bring you an easier way of assessing chance creation and defensive vulnerabilities. In order to grasp the idea of the visual properly, let’s understand what xA is.

To put it simply, the xA of a pass is the probability of it turning into an assist. This means that only passes that end with a shot (also known as key passes) have an xA value.

There are multiple factors that go into calculating the xA of a pass, but we shall avoid delving into them for simplicity’s sake. Basically, high xA = high creation. Hence, generating a high xA while attacking is good, but conceding high xA while defending is bad.

Now, in the visual below, we have divided the pitch into 29 zones. Due to limitations in the data set, there is a minor discrepancy in calculating the xA of key passes that come from the defence and the middle of the pitch.

Therefore, the visualization of xA in those zones may be slightly askew. However, most of this article is based on a team’s creation in the final third which is reliably calculated and the remaining analyses have been made taking these inconsistencies into cognizance.

Using our numbers, we created four visuals for each team – two visuals showing the xA generated and conceded by the team per zone on an individual case, and two more visuals showing the xA created and conceded compared to the league average.

Aided by these tools, we can easily identify:

  • Which areas a team likes to attack from?
  • How effective they are at it?
  • Which defensive area do they concede the most from?
  • How well they manage the opposition’s threats?

Although, it is a primitive foray into geo-mapping, it could prove to be a quick way of assessing a team’s activity and performance.

Having watched Mumbai City FC from the stands and the screen all season long, it is the team I turned to first for verifying this method. As time passes, I will cover and analyze other clubs using this methodology.

For now, here it is:
A breakdown of Mumbai City FC’s offense and defence using xA HeatMaps.


MUMBAI CITY FC IN ATTACK


Mumbai City FC 2019-20 xA Expected Assists HeatMap Individual
The more xA generation a zone sees, the redder it gets.
This shows which zone a team tries to play its final ball from.

At first glance, it’s evident that Mumbai City FC preferred their balls coming in from the wings. And which team wouldn’t when they have Diego Carlos and Modou Sougou at their disposal? In outgoing coach Jorge Costa’s defence, there was nothing wrong with his inclination to use the wings.

However, the relative scarcity of passes from outside the box is telling of Mumbai’s struggles. Raynier suffered from injuries and found his time in the hole to be sporadic.

Mohamed Larbi on the other hand was less influential than people expected him to be. Having been given the tag of ‘big money signing’ almost immediately, the playmaker had huge expectations to fulfill. But his finishing and creativity left much to be desired to the Islander faithful’s chagrin.

Individual performances aside, it was also the tactics that went wrong. With Larbi instructed to support play on the left, very rarely did the Islanders find a strong attacking presence in “zone 14 (the hole).” Their go-to method of attacking was to play floated balls to a 5’9” poacher – a tactic that is flawed at its very core.

The midfield saw a fair share of key passes too. The idea of releasing balls for forwards from the middle of the park was a good one. Goals against Hyderabad FC and Bengaluru FC were a result of this tactic.


Mumbai City FC 2019-20 xA Expected Assists HeatMap League Relative
If a zone is on the blue color grid, it sees lower creation than the league average.
Conversely, an orange zone sees more creation than the league average.
The more orange we see in the team’s preferred areas, the better.

The HeatMap above shows the xA difference (xA generated by club in zone – League Average of xA in zone). It gives a reference point to understand how effective the club’s modes of creation were.

For example, let us consider the right wing. As we noticed in the previous graph, it was used very frequently. However, if we transpose it to this graph, it tells us that the right wing for Mumbai created a lower xA as compared to the league average. This means that even though the right flank created a good chunk of chances for the team, it was inadequate as compared to the rest of the league. The left on the other hand looks promising as it created more than the league average.

This can also be verified by the eye test. Sougou failed to replicate his influence from last year having completed only 17.65% of his dribbles and attempting a meager 1.66 crosses per 90. Although he played as a second striker at times, his numbers were poor for a player who was tasked with creation. Sarthak Golui and Souvik Chakrabarti played conservatively as well which made it tougher to create more from the right.

On the other hand, Diego Carlos was dynamite. He regularly found his way around his man and attempted 4.54 crosses per 90. Had there been a target man in the box, he would have had more than the two assists he racked up. Continuing on the full-back discussion, Subhasish Bose was far more aggressive as he regularly bombed ahead and put balls into the box from the left.

As seen earlier, the area outside the box is frigid. The glaring lack of creation from here is proof of how service for Chermiti was in short supply. Had he received as much as his striker counterparts, MCFC would have made it to the play-offs.

Lastly, Mumbai also played more direct balls from the heart of midfield as compared to other teams. Rowllin and Machado’s ball playing abilities were well utilized and added versatility in their attack.

With Jahouh accompanying Rowllin in the new season, we could see this part of the graph grow much darker in the forthcoming season.


MUMBAI CITY FC IN DEFENSE


Mumbai City FC 2019-20 xA Against Expected Assists HeatMap Individual
The more xA a zone concedes, the redder it is.
This shows which areas the opposition decided to pick out while playing Mumbai

Having covered the attacking zones, we will now look at the chances Mumbai conceded while they were defending. Again, the flanks are crimson with the left darker than the right. This is because it was an easy option to progress directly when Subhasish or Carlos lost possession.

The right is relatively lighter because the right-backs played a more defensive role. They were caught out less often and were able to stick to the opposing wingers. However, knowing that Souvik Chakrabarti struggled with the ball at his feet, it is also possible that teams decided to press him and create after regaining possession in that space.

Lastly, opponents created plenty from central areas too. The reason for this is fairly obvious – attacking centrally is more beneficial than attacking wide. However, xA conceded by Mumbai from outside the box was not very threatening as we will see in the next section.


Mumbai City FC 2019-20 xA Against Expected Assists HeatMap League Relative
In this case, the bluer the better as the team concedes lesser xA than the league average in those zones.
A tendency towards red is a sign of danger as the team is defending poorly in that area.
Conc Rat (Conceding Ratio) = xA conceded by league in zone – xA conceded by team in zone.

Being a protégé of Mourinho, one of the tenets of a Costa team is a resolute defense. Conceding the second lowest number of goals in the league stage in the 2018-19 season, the team built a reputation for taking no prisoners.

Sadly, the same adamant defending was nowhere to be seen this year. Letting go of Lucian Goian was an amalgamation of everything they missed this year – a strong central defender who did more than the ordinary.

While the wide spots and the area outside the box were well-guarded, the lack of co-ordination within the box was what hurt Mumbai the most. Their replacements for Joyner Lourenco and Lucian Goian were insufficient as the 2019-20 backline conceded nine goals more than the previous season’s team.

One of the reasons for this was the injury list they had to deal with. Anwar Ali was ruled out indefinitely before the campaign started and Mato Grgić got injured in the first match. Though the Pratik Chaudhari-Sarthak Golui duo put in a good shift, it was inferior as compared to the foreign CB partnerships most clubs used. Even after Grgić’s return, the backline never seemed to settle and continued leaking goals. This time, the gamble of using an Indian center-back backfired on them.

The full-backs dealt with one-on-one challenges in a fine manner, but they were unable to cut out balls played in behind them. Due to this, we can see orange squares on either side of the goal. Teams like FC Goa regularly exploited this as their players ghosted into the spaces between the full-back and centre-back, and played in deadly cutbacks or had a free shot on goal.

Uncharacteristically, this year’s defensive organization was in disarray. An improper press made it easy for teams to progress into midfield and play long balls. Though aerial threats were well-handled by the defenders, they tended to lose focus and committed too early when the ball was on the ground. While defending set-pieces, players were regularly caught off-guard by movement in the box and left their marker. With such a penetrable defense, it is no surprise that Mumbai kept only four clean sheets in the campaign.

CONCLUSION

Now that we have a comprehensive idea of the Islanders’ performances in attack and defense, it is easier to understand why they finished fifth in the 2019-20 ISL.

Though there were certain positives, there were also an element of naivety in the way they played. A final goal difference of -4 makes it difficult to know whether the forwards should have scored more or the defenders should have conceded less. Questions about pushing Sougou out to the wing and expecting Amine Chermiti to head in crosses will be left unanswered as Costa and his foreigners have left the club. Perhaps, it was this dysfunctionality that led to Mumbai finishing just outside the play-off positions.

However, with fresh investment coming in from the City Football Group takeover, a new and proven manager in Sergio Lobera and several illustrious signings on their way, Mumbai City seem well-equipped to challenge for the league title and probably reach the ISL championship final for the first time in their history.

2 Comments

  1. Umang J. Umang J. 24th September 2020

    Superb!!
    Increase my knowledge by a ton!!

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