The Week in Stats: Ronaldo has blunted Juve’s attack

This week we take a closer look at Serie A leaders Juventus, with particular focus on how Cristiano Ronaldo has changed the team’s performances.

Having recently assessed how the top teams in La Liga were faring in comparison to the same point last term, we’ll now turn our attention to Serie A leaders Juventus, who sat eight points ahead of Napoli on Christmas Day.

The big question this season is, of course, how the $128 million signing of Cristiano Ronaldo has affected Juventus.

And the answers to that question may well come as a surprise to some. Two things are clear from the chart above. Firstly, Juve’s defensive numbers have improved markedly this term.

Juventus remain undefeated domestically in the current campaign, but they’d already lost twice at this juncture last term – at home to Lazio and away to Sampdoria – although they were beaten only once more during the rest of the campaign.

Juve have also conceded four fewer goals (eight compared to 14) and have restricted their opponents to lower quality chances overall – their xGA totals after 17 matches has fallen from 15.91 to 12.17.

The second obvious take-away is that Juve’s attacking figures are conspicuously lower than last term as well.

They’ve scored ten fewer goals, and that’s a remarkable decline. The big difference here is that Juve have yet to truly put anyone to the sword in Serie A this season. Juventus haven’t scored more than three goals in any league match, whereas last term they’d already put six past Udinese and scored four against Genoa, SPAL and city rivals Torino.

Juve’s xG figures shed some light on this development. Last term, 17 games in Juventus had scored 44 goals from just 28.22 xG of chances, which is an extraordinary over-achievement.

Perhaps even more remarkably, this was something they were able to sustain right through to the end of the season: Juve ended the 2017-18 campaign with 86 goals against an xG of 59.23.

In sharp contrast, so far this term Juventus have scored 34 goals from 33.36 xG of opportunities. So in the space of less than half a season, the standard of Juventus’ finishing has gone from extraordinarily effective to quite literally average. Despite having by far the most expensively assembled forward line in Italy, they’ve been converting chances at a rate slightly below that expected of an average side.

And this, of course, is where a certain Cristiano Ronaldo enters the equation. Numerous analytics articles over the years have concluded that Ronaldo is, at best, a very average finisher. It’s a point underlined by this excellent piece from earlier in December 2018.

For example, every season from 2010-2018, Ronaldo took both the most shots and the highest number of off-target shots per 90 minutes of any player in La Liga. His shot volumes rather than conversion rates have always been the most remarkable aspect of his play.

So it should perhaps come as little surprise that Juve’s shot numbers in the first 17 matches of the season have gone up from 279 to 320, while the team’s conversion rate has plummeted from 15.8 percent to 10.6 percent this term.

Ronaldo himself has taken a league-high 119 shots to date. Lorenzo Insigne of Napoli comes in a distant second with 73, while no other Juve player has taken more than Paulo Dybala’s 34.

And if we look at the effect that Ronaldo’s arrival has had on the other members of Juve’s forward line, it’s immediately conspicuous above that Dybala’s attacking numbers have gone through the floor.

At the same point in the 2017-18 campaign, Dybala had already scored 12 league goals. This season, he’s only found the net twice, despite playing 30 minutes more. Similarly, the Argentine striker’s shots per game average has fallen from 4.3 to 2.3.

Ronaldo’s many fans certainly can’t claim that Juve’s newfound profligacy in front of goal is due to his teammates. In terms of xG under-performance – in other words, how wasteful Ronaldo is being with the chances he’s enjoying – he isn’t just the least clinical player in the Juventus squad. He’s also the worst performer in Serie A as a whole this season. At least Ronaldo’s Juve colleague Mario Mandzukic is doing his best to pick up the slack.

Of course, none of this will matter to Juventus should Ronaldo’s arrival bring them the holy grail of the Champions League trophy in July 2019. And despite Juve’s diminished attacking performances, the Turin giants were still eight points clear at the top of the table over Christmas.

But the underlying numbers nonetheless point to Ronaldo having failed to improve – or even maintain – Juve’s excellent attacking figures from the same period last season.