Ignoring the obvious difference in league placing, it’s clear as day that Aston Villa have made a big step forward this season from where we were last season - from avoiding relegation to challenging for European places at points this season.
But has it all been a fluke? Was it just the stars aligning in our favor? Do we deserve to be where we are based on our performances?
In this piece, we’ll take a look beneath the surface and dive into the numbers to see just how good Aston Villa’s heavily lauded defense has actually been this season.
The first place for us to start is with expected goals (xG) and expected goals against (xGA). Last season, Villa accumulated a total of 40 xG and conceded 65.7 xGA. Now, if we put this against the actual totals of 41 goals scored with 67 goals against, we can see that we under-performed by -0.3 xG overall, which is minuscule and shows we deserved to have finished where we did and that our performances matched our results.
This season, however, we have an xG of 47.4 contrasted to an xGA of 44.9. This makes for interesting reading when we look at our actual results of goals scored of 48 and goals conceded being 38. We can see we have over-performed expected goals by +7.6 in which is a huge margin. Now, I know what you may be thinking; “Isn’t it good that we’re over-performing?” Well in short, no. Not really. Let me explain.
Let’s add in just a bit more context to these numbers.
By using all of our goalkeepers from last season, we had a post-shot expected goals minus goals allowed of -6.2. This metric measures how likely a goalkeeper is to save a shot, with positive numbers suggesting either better luck or an above average ability to save a shot. Put simply, our goalkeeping was woeful last season and that is not a surprise to any Villa fan after enduring the displays of Nyland and company.
This season, we have a post-shot expected goals minus goals allowed of +8; almost the exact number by which we are over-performing this season and this is no coincidence. This illustrates what everybody who has watched Villa this season already knows - Emi Martinez is an absolute concrete wall!
However, there is a caveat. Whilst Martinez may be an elite shot-stopper, there is still a chance that he may just be having a very good season and going through an extended purple patch. Here lies the issue; if Emi Martinez was to perform as expected (i.e., having a post-shot expected goals minus goals allowed of zero) Villa would have conceded almost eight more goals! A staggering number over the course of the season.
This shows us that our defense is not as water-tight as it appears, but that Emi Martinez is simply having an unbelievable season and that with a goalkeeper who performs as expected, Villa would be significantly worse off. Imagine how many points we’d have dropped and how far down the table we’d be without this over-performance. As amazing as it is having a magnificent keeper in our resident Argentine behemoth, we should not have to rely on him so much and we must get a lot better tactically as right now, we are not good at stopping the opponent from creating chances.
Let me just add that there is every possibility that Martinez outperforms his post-shot expected goals minus goals allowed next season too and the season after that and so on. But to be the side we want to be in which is a side that is always in the top half of the table, is challenging for Europe, and making good runs in the cup competitions, we cannot just hope that our goalkeeper over-performs constantly as in all likeliness, it won’t last.
We must improve the defensive aspect of the side even further and work on reducing the number of chances we concede as well as the quality. If we do not, then we may not progress as we may like or conversely, we may even slip down the table and the last thing anyone associated with this club wants is another relegation dogfight. It is essential that we look into these underlying numbers and interpret them correctly, otherwise, we risk becoming ignorant and oblivious to our issues now and in the future.