14We debated on the most recent Huddle Breakdown (please subscribe) regarding centre-backs and aerial duels and how helpful or not the available data is.
This was prompted by the performances of Liam Scales and Stephen Welsh in the Scottish Cup match versus Livingston. The opponents, as is typical in Scotland, had the proverbial “big lad” up front (and indeed seemed to have prepared for a basketball match as opposed to association football), and in totality Scales “won” 11 out of 18 aerial duels and Welsh only two from five.
The question is whether “winning” a duel can irrevocably be labelled a “good” thing” or whether there is far more nuanced. You can probably guess the Answer.
When tagging aerial duels I record one of four outcomes.
Player wins the duel and his team gains possession;
Player wins the duel but the opponent gains possession;
Player loses the duel but his team gains possession; or
Player loses the duel and the opponent gains possession.
Duel Win %
For centre backs with data recorded against them and having a total of more than 900 minutes, here is the very simple percentage of category 1 and 2 above as a ratio of the total number of aerial duels.
The average is 78% duel success as regards who “wins” the header.
Both Scales and Welsh fall below that average joined only by the six-foot-three Jack Hendry.
Good ol’ Shane Duffy was the classic case of recruiting for a specific skillset (“aerial dominance”) without considering the holistic profile of the player (used to a low block; used to “defending” as opposed to possession dominance; not used to a high line; not used to being protected by an ageing pivot; not used to covering attacking fullbacks).
By my goodness could he win a header!
Filip Benkovic remains a big regret.
And Carl Starfelt has a slightly better duel win percentage than Cameron Carter-Vickers! Who knew?
So, this tells us about whose noggin connects primarily with the ball in the duel.
If we focus on “what happened next” we get a slightly different perspective.
Dominant Duel Win %
Let’s be radical and invent a new data label. Let’s call those aerial duels where both the hooped noggin prevails AND the ball ends up in Celtic’s possession as a Dominant Aerial Win.
Here are the same players with their “win” percentages on this basis.
The average of win/wins is only 35 percent.
Look at Starfelt – his dominant win percentage is a mere 21 percent, alongside the hapless Hendry. Meaning that only 21 percent of aerial duels did Starfelt win the header and Celtic got possession. Welsh remains below average.
Scales manages to exceed average and surprisingly match Christopher Jullien for dominant win percentage.
However, none other than Carter-Vickers gets over the 40 percent threshold for dominant aerial wins.
Why Does This Matter?
Scottish football is dominated by long ball play, and nearly all sides have an aerial combative striker or two.
Celtic are usually the smaller of the teams physically, and therefore sides play for set-piece opportunities whether that be long throws of corners and free kicks. Loading the ball into the box and fighting for the ball in the air neutralises most technical aspects of the game other than anticipation, jumping, strength and timing. All cheaper attributes to recruit for over ball control, technique, vision and other such frippery.
Centre-back duel success is important as regards how many of these opportunities the opponent gets. If your centre-back is “dominant” then those opportunities are reduced.
My point about Scales in particular is that yes he “wins” a fair share of aerial duels but often the next action is an opposition throw or corner or it is otherwise random where the ball ends up. This is the type of chaotic football a possession-dominant team like Celtic should seek to minimise.
Welsh simply isn’t suited to Scottish football from this perceptive. The mooted move to Italy from a couple of seasons ago would make perfect sense for his strengths.
This view also allows me to better articulate some of my reservations about Starfelt. Again, yes he “wins” most aerial duels but it isn’t clean, it did not lead to control. It leads to chaos and often opposition possession. Scales is similar.
We continue to search for a similarly dominant centre-back to partner Carter-Vickers.
Where dominant means wins the duels AND maintains possession for Celtic.
Dominant aerial win % - good idea