Changing Your Luck
Celtic scored 147 goals in winning a treble last season, in all competitions. 2.77 per game.
This season was always going to be some kind of transition from Ange Postecoglou to Brendan Rodgers and we do not have to rehash the recruitment story.
Those goals came from shots rated with an overall xG of 139. Some nice overperformance then but not ludicrously so.
This term Celtic are averaging 2.18 goals per game and with a maximum of 10 matches left in league and Scottish Cup, are on track to hit 108 goals.
Those are currently coming from xG of 102 – 2.23 xG per game. 87 goals so far from 102 xG is quite an “under” performance.
2022-23 Player
At the player level, here are all those who played at least 5 matches or more in terms of their individual goals to xG per 90 minutes differential:
Kyogo Furuhashi had an exceptional season and many of his goals were from inside the six-yard box and central and probably underestimated using the basic xG model I have.
Many of the “over” achievers were those that often came off the bench and gorged on tiring opposition – James Forrest, David Turnbull, Oh Hyeon-gyu.
Giorgos Giakoumakis and Matt O’Riley were notable for their “under” performance relative to their xG.
But the general point here is that half the squad over-performed their xG and half underperformed, roughly. Let’s call it a “normal” distribution.
2023-24 Player
This season we know as a team that some mean reversion hoodoo is going on, but how does that manifest at the player level?
Eeek.
Only three players are in the overperforming category, and one is now sitting on Cardiff City’s bench whilst the other two, who cares?
Top scorers Furuhashi (15) and O’Riley (11) are nearly at 0.1 goals per game under their xG.
Why does this happen?
You would have to go through each shot and categorise:
Poor finishing
Good goalkeeping/defending
Bad luck
Likely for each player, it is a combination of all three.
Let’s consider some fundamentals:
Celtic are taking LESS headers as shots (always lower xG efforts) and the same proportion of shots inside and outside the box as last season.
Those would be two obvious areas to consider.
The one major difference is shots taken from Zone 1 – central to the goal within the six-yard box – very high xG territory. That has fallen from 10 percent of all shots to seven.
Celtic need to get back to the low, hard cross across the six-yard box and utilise the special movement skills of Kyogo to get on the end of them – simples!
As well as getting on the right side of the variability of football in terms of finishing skill, goalkeeper performance and sheer luck, naturally.