An analytical comparison of Chelsea and Manchester City’s WSL teams

A newly expanded WSL gets underway next month, with reigning champions Chelsea facing last season’s runners-up Manchester City on the opening day.

As well as enjoying an unbeaten season, Chelsea finished 2017/18 with the league’s best defensive record and capped off a fine campaign by winning the FA Cup.

Last season also saw both sides reach the Champions League semi-finals, which is the first time two English clubs have reached that stage, providing an indication of the growing strength of the WSL as it now enters a new era, with every top-flight team now being fully professional.

Ahead of their opening day clash, we take an analytical look at last season’s top-two to get a better understanding of why they were successful and the potential impact their summer signings could have on their performance.

Approach in possession

In the majority of matches played last season, Chelsea operated with three central defenders, with wing backs operating high up the pitch to create a midfield four in either a 3-4-3 or 3-4-1-2. Manchester City consistently played 4-3-3.

Taking into account matches against the top-six sides only, Manchester City attempted the most passes per 90 minutes (507.2) of any team in the league. On average, Chelsea attempted over 57 fewer passes than City, which was less than third-placed Arsenal.

2017/18 WSL attempted passes per 90 minutes

*= only matches against top six teams

Chelsea’s slightly more direct approach is highlighted by the fact that two of their central defenders, Millie Bright and Magdalena Eriksson, attempted more passes into the attacking third per 90 than any other Chelsea player, 13.3 and 10.6 respectively.

However, this doesn’t mean they were always taking a long ball approach – the back three often adopted a high line and in the case of Eriksson, a lot of successful passes were played into wide left areas for the left wing back or centre forward Fran Kirby when she drifted out wide, as highlighted by the pitch map on the left below. When she did attempt longer passes from deeper positions, they tended to be more unsuccessful, as shown on the right. Her average pass distance for completed passes was 21.5 metres, whereas for unsuccessful passes her average was 29.3.

WSL 2017/18 Magdalena Eriksson open play passes into the final third

Based on data from matches against top six teams

Manchester City’s more possession-based approach can be further analysed through the sequence framework. City were more patient in their build-up play, moving the ball upfield at a slower pace compared to Chelsea, whilst at the same time also having more passes per sequence than any team in the league.

Adopting a successful high press

One trait shared by City and Chelsea last season was a desire to win the ball back high up the pitch. When out of possession, the front three and midfield would look to press and recover the ball in advanced areas, which resulted in Chelsea completing 9.83 ball recoveries in the attacking third per 90, with Man City completing 9.72. These were the two highest totals in the league.

At individual level, of players who played at least 50% of available minutes last season, four Man City forward and midfield players featured in the league’s top 10 for recoveries. Another player listed, Caroline Weir, has also signed for City this season which suggests she will be well suited to winning the ball back in advanced positions.

WSL 2017/18 attacking third ball recoveries 

*= players who played at least 810 minutes listed

Creative outlets

As well as leading the way on attacking-third recoveries, Fran Kirby is vitally important to Chelsea’s attacking play.

Although she is often the highest player on the pitch, she has a tendency to drop deep into pockets of space and either link-up with a teammate or take-on an opponent directly. In 2017/18 she was Chelsea’s leading scorer (8), assist provider (6) and had the most take-ons (68), with a success rate of 54%.

Returning to the Opta sequence framework, we can also see that Kirby was involved in more sequences ending in a shot than any other Chelsea player, highlighting how involved she is in Chelsea’s attacking build-up.

From Manchester City’s perspective, we can see how important Nikita Parris and Claire Emslie, who played on right and left of their front three respectively, were in shot-ending sequences. Izzy Christiansen was also heavily involved from central positions and following her summer departure to Lyon, City will be hoping that Caroline Weir will be able to replicate her form for Liverpool last season in their new-look central midfield.

WSL 2017/18 involvement in shot-ending sequences

Composure in front of goal

Manchester City scored the most goals in WSL last season with 51, however when we focus only on games involving top-six sides, they scored exactly the same number of non-penalty goals as Chelsea (17), with a further 3 from the spot.

When we look at the number of shots and chances created in these matches, City lie only third, with a lower xG per 90. However, they massively outperformed their xG by 0.56 per 90, which indicates they were converting a larger volume of difficult chances into goals. This is backed up by their xG per shot ratio, which was identical for the top three teams – City were just more clinical.

Based on data from matches against top six teams

As we can see from the pitch maps below, Manchester City were particularly productive around the edge of the six-yard box against top-six sides – with six of their 17 non-penalty goals coming from headers. In fact, one in four of their attempts on goal came from headers and Claire Emslie, on the left of their front three, delivered the most crosses in the league per 90 mins (12.1).

Chelsea’s goal location is similar; however we can see they failed to convert a lot of high probability chances from good positions centrally.

Both teams were willing to shoot from distance and their goal tally from shots taken outside the area exceeded their xG. Chelsea scored three goals (xG 1.37) and City scored twice (xG 1.55).

WSL 2017/18 goal attempts

Goal attempts in matches against top six teams

Key changes this summer

Both Man City and Chelsea have been busy in the transfer market, bringing in players from both home and abroad.

Eniola Aluko has moved to Juventus, but was a fringe player for Chelsea last season. The Blues have reinforced their forward line by signing Finnish international Adelina Engman from Göteborg FC.

More notable departures are defenders Gilly Flaherty and Gemma Davison, who have moved to West Ham and Reading respectively.

They have been replaced by two full backs, New Zealand captain Ali Riley and 20 year-old England youth international Jess Carter, who has joined from Birmingham, along with central defender Sophie Ingle from Liverpool.

Carter first appeared in WSL at the age of 16 and already has 60 league appearances. Last season she was involved in more duels (216) than any other right back, winning 53.7% and completed 162 recoveries, the fifth highest of any player in the league.

One noticeable difference between Carter and Davison is touches in the attacking third – Davison (30.99) had nearly double the number of Carter (16.9), so Carter will be expected to be more involved offensively this season if she is going to be utilised as a right wing back frequently. However, if we look at her heat map for Birmingham last season, we can see that she does like to get forward, which may have been a key consideration during Chelsea’s recruitment process.

WSL 2017/18 Jess Carter heat map

Wales captain Ingle sat fourth in total league recoveries last season, but what stands out is that when in possession, she averaged 9.5 attempted passes per 90 into the final third – the second highest of any Liverpool player, which suggests she will fit well into Chelsea’s playing style.

Chelsea will also be strengthened by the return of Karen Carney, who missed three months of the season through injury. In the eight games she played, she created 4.95 chances per 90 and had an xA of 0.47/90, the second highest in WSL.

As mentioned earlier, City’s key departure is Izzy Christiansen, who was their leading chance creator last year and scored nine goals. City have brought in Caroline Weir from Liverpool, who not only created the same number of chances (30), but was also involved in an almost identical number of shot-ending sequences, 96 to Christiansen’s 95.

City have also brought in three forwards: Belgian striker Tessa Wullaert from Wolfsburg, Janine Beckie from NWSL side Sky Blue FC and 17-year old Lauren Hemp from Bristol City. Beckie has demonstrated her versatility this year by playing on the left and in central midfield as well as up front for Sky Blue, whilst last season Hemp scored seven WSL goals and was involved in 78 shot-ending sequences, substantially more than any other Bristol City player. The next highest had 46.

Their final major capture is defender Gemma Bonner from Liverpool, who had the second-highest aerial success % last season (80%) of central defenders who competed in 30 or more aerial duels.

More of the same in 2018/19?

Chelsea and City’s summer reinforcements suggest that both teams’ approach this season is going to be similar to that we saw in 2017/18, however Chelsea did change their formation to 4-3-3 for their opening Continental Tyres Cup game against Brighton over the weekend.

Whilst City were Chelsea’s closest challenger, their overperformance on expected goals against top-six sides highlights that they will need to create more higher quality chances if they want to seriously challenge for the title, especially if their goal output reverts to the mean. Chelsea’s underperformance on xG also suggests they have the potential to score more if they are more clinical.

Both teams will be wary of Arsenal, who have been busy in the transfer market strengthening their midfield and defence – signing four players from abroad. However last season they were the lowest scorers in the top four – with their top scorer Beth Mead (8) massively overperforming her xG (4.90). Mead and Jordan Nobbs are their two key attacking players – between them they created 42% of all their chances, so if teams can limit their influence that could harm Arsenal’s chances.

Likewise, Chelsea will be hoping that Carney stays fit and that Kirby maintains her levels of performance shown during the last campaign. If they do, they could again be the team to beat this year.