I went through every Champions League and Premier League match this season looking for a reason why David Ospina is preferred to Wojcich Szczesny and I honestly can’t find one.
But what I did find was a stat which I think proves beyond a doubt the impact that Francis Coquelin is having on Arsenal’s defense.
First, Szczesny’s been in and out of Arsenal’s starting lineup three times this season. Once for a red card, once for a hip injury, and once for a poor performance in the Southampton game.
This gave me a chance to compare numbers for three different keepers this season: Szczesny, Emiliano Martinez, and Ospina. I looked at their stats and the only number that really popped out at me was the number of ‘big chances’ that each keeper faced.
Martinez is a bit unlucky in this regard, his sample size is small so it is artificially inflated by the terrible Stoke City match, where Stoke ran rampant over Arsenal’s midfield and created four big chances. But the telling stat was that Szczesny faced 1.67 big chances per game and Ospina faced a paltry 0.55.
Just in case you don’t remember, ‘big chances’ are the Opta stat which counts the number of clear-cut shots that a player has on a defence. These are those one-on-one moments and close-range shots where we would normally expect to see the opposition score.
Arsenal had 96 of these chances (in both Premier League and Champions League) and scored 45 (47 per cent conversion rate) and the opposition had 49 and scored 21 (43 per cent conversion rate).
In real numbers, Szczesny has played 21 matches in both competitions and faced 35 big chances. He’s only saved 11, he’s allowed 14, and 10 were off target. That means he has a 44 per cent save rate (shots on target that he saves) against big chances.
Ospina has played 11 matches but critically, he’s only faced six big chances, saved two, and allowed three (a 40 per cent save rate on a terribly small sample).
Just to put that into perspective, Ospina has faced 0.55 big chances per game. Szczesny was looking at 1.67 per game. More then three times as many!
If we look at this work-rate from a saves perspective, Szczesny was saving Arsenal a big chance goal every other game and Ospina is only saving Arsenal a big chance goal every 5.5 games.
One could actually argue that given the normal conversion rate of these shots and that Szczesny made 11 saves, he saved Arsenal more points than Ospina did. Ergo, one could say, Szczesny is the better keeper.
I’m not going that far. I think Ospina hasn’t been pressured enough for us to know if he is at the same level or better than Szczesny. Facing six big chances is, let’s just be honest, not a lot of work to judge someone by.
However, if we are interested more in the process than in the outcome we have to ask “why did Ospina face so many fewer big chances than Szczesny?” The answer is Coquelin.
Arsenal have used four different defensive midfielders this season: Mikel Arteta, Mathieu Flamini, Calum Chambers, and Coquelin. Coquelin has played 13 games this season and in those 13 games Arsenal have only faced 11 ‘big chances’.
In the other remaining 24 games, Arsenal faced 38 big chances which is an average of 1.58 per game. In other words, just having Coquelin on the field has meant that Arsenal faced almost half the number of big chances than they did without him.
But wait… like a fine French, it gets better.
This first appeared on 7amkickoff on March 20
Coquelin started two matches with another defensive midfielder next to him: Flamini against West Ham and Chambers against Southampton. In those two matches alone, Arsenal faced five big chances. I suspect that this was down to the confusion of place which many Arsenal players feel. What is Coquelin’s job when he’s playing next to Chambers? Or Flamini?
If we remove those two games and only look at the 11 matches in which Coquelin has been Arsenal’s only outright defensive midfielder, Arsenal have faced just six big chances. 0.55 per game. The same number that Ospina has faced.
It looks to me like Coquelin is making it easy for Ospina and the rest of the defence.