Liverpool will face Atletico Madrid on Tuesday 18 February in what many consider to be the battle between the two best goalkeepers in the world today: Alisson of Liverpool versus Jan Oblak of Atletico Madrid. Although, trying to compare them can be something of a fool’s errand as it mostly highlights their contrasting styles.
I have previously covered the brilliance of the World’s Best Goalkeeper prior to Liverpool facing Flamengo in the final of the Club World Cup back in December 2019. However, with all due respect to Rubro-Negro #1 Diego Alves, Jan Oblak is on another level entirely. He is the goalkeeper who both fans and data analysts will agree has been at the top, or thereabouts, in each of the last five seasons in terms of being the world’s best shot-stopper.
While his numbers still stack up well against the majority of goalkeepers this season, he is dipping well below the high bar he has set for himself in past seasons. Since signing for Atletico Madrid, he has performed at 150% better than expected goals models predict on average. However, this season he is coming in at ‘only’ 110%.
In fact, the only seasons in his career in which he has saved a lower percentage of shots than his current season are 2011/12 and 2012/13, when he was still a teenager playing for União de Leiria and Rio Ave, in Portugal.
The reasons are open to the interpretation, of course. This could simply be variance that you find when taking a relatively small sample from a much larger pool of data. Would these numbers look better if you looked at the last thirty-eight games? Or if you simply ignored the first few games of the season when he conceded four goals from eight shots?
Another factor could be the departure of Diego Godin to Inter Milan, the centre back many considered to be the main rival to Virgil van Dijk for the title of world’s best defender. Looking at the scatter graph above, we can see that the goalkeepers who faced the ‘easier’ shots on average are to the left and those who faced ‘more difficult’ shots are on the right.
It appears that only a handful of goalkeepers have faced easier shots on average than Jan Oblak this season; most of whom are in Ligue 1. This suggests that the Atletico Madrid defence is still doing their job of limiting the quality of chances that opponents are able to create against them. We can also see that Oblak is falling below the average line for shot quality versus save percentage.
What we can also see on this graph is Alisson soaring above the average line. While the shots he has faced this season fall around the central cluster of players, similar in quality to the likes of Rui Patricio at Wolves or Nick Pope at Burnley, Brazil’s #1 has pulled the steel shutters down and put up a sign notifying the Premier League’s strikers that the area is strictly off-limits.
If you isolate only the Premier League’s top twenty goalkeepers this season in terms of quantity of saves made, then look at performances in terms of goals conceded versus expected goals, exactly how much of an outlier his numbers are really begins to sink in. He is performing at a whopping 252% above what expected goals models predict. To put this number into perspective, the best season in our dataset by any goalkeeper prior to this one, is that of David De Gea’s ‘Superman’ season in 2017/18, where he outperformed expected goals by 171%.
The fact Alisson missed a chunk of the season due to an Achilles injury seems to be precluding him from talk of the Premier League’s Player of the Year award. Yet we are perhaps witnessing one of the all-time great goalkeeping seasons in the Premier League. Petr Čech’s 2004/05 season, where he had an identical 87% save rate and 0.37 goals against per 90 being the current holder of that particular crown.
Yet, unbelievably, there is perhaps still room for Alisson to improve.
In terms of big chances, we can see above that he has been saving at below league averages so far this season. Although, this could just as easily be variance given the relatively low number of big chances faced this season. Last season, for example, Alisson saved 48% of the big chances faced; 8% above the league average.
Also, if we consider those first five games after his injury as part of his recovery period, his form since settling back into the team is truly frightening. He has conceded just one goal from twenty-eight shots (or a 96.4% save rate) in his last ten league games.
Of course, the main difference between Alisson and Jan Oblak is a stylistic one. You can now categorise goalkeepers as those who stay on their line and focus on shot-stopping as ‘Line Keepers’ (e.g. Mignolet, De Gea, Oblak, Pope), while keepers who are aggressive in their attempts to prevent shots entirely and want to help their side play out from the back are referred to as ‘Sweeper Keepers’.
The thing that makes Alisson interesting is that his shot-stopping numbers stack up well against more traditional ‘line keeper’ while also performing at a high level as a sweeper, as we saw against Norwich on 15 February 2020 with his fantastic tackle to deny Teemu Pukki a tap-in.
Criminally underrated save by Alisson against Norwich…
Done well to rush out and read Rupp’s attempt to square it to Pukki.
Was insane at real time!#LFC
— RouteOneFootball (@RouteOneFootyy) February 15, 2020
As there was no resulting shot from the above passage play, this isn’t included in any of the shot-stopping metrics quoted above. This is what is referred to as ‘shot prevention’. To bastardise Wayne Gretzky’s famous quote: ‘you save 100% of the shots you prevent’. This is an undervalued and difficult to measure skillset in goalkeeping.
However, comparing the two starting Goalkeepers for Liverpool and Atletico in terms of sweeping, we can see Alisson averages 0.70 clearances per 90 compared to 0.25 for Oblak. The Brazilian also averages 0.58 runouts per 90 to just 0.08 for the Slovenian.
In terms of crosses, while Oblak needs to deal with more crosses with 0.51 to Ali’s 0.41 per 90, Oblak is only challenged on 8% of the crosses he comes for. Alisson is challenged on 42% on the crosses he claims. This would suggest Alisson is braver in coming out and attacking the ball in the air against opponents, while Oblak tends to only come out for balls what he can claim unchallenged.
One final way goalkeepers prevent shots is through keeping possession of the ball for their team. There is a proven correlation in football between conceding possession of the ball in your own half of the pitch and giving up a shot within the next ten actions on the pitch.
In this sense, Alisson is one of the best in the game alongside his Brazilian international teammate, Ederson. His passing accuracy is 83.6%. In contrast, Oblak’s passing accuracy is a woeful 54.6%. Essentially, when Oblak has the ball, half of the time he just returns it to the opposition.
So, while Oblak has an intimidating reputation as a goalkeeper, the man every team should be frightened of facing in his current form is Liverpool and Brazil’s #1: Alisson Becker.
All data and graphics used in this article are provided by @CraqueStats.