I still maintain the biggest issue Celtic have faced this season is not finishing off their chances.
There are undoubtedly many concerns for Postecoglou to address:
A settled defence
First choice left back
Curing the hamstring epidemic
How to operate a midfield with no natural “8”s
The never-ending striker shortage
Lack of aerial presence in defence
And so on and so forth…..
But it is in the taking of chances where there seems to be room for most improvement. Remember: Celtic are leaving about 0.8 goals on the pitch each and every SPFL game – i.e. their xG is 0.8 higher PER GAME than actual goals. This equates to 30 goals over a season!
Clearly material in a tight title race.
SC vs xSC
SC is Scoring Contribution = Goals + Assists per 90m.
xSC is Expected Scoring Contribution = xG + xA per 90m.
The underperformance of goals vs expected goals seems to extend across the squad.

Of the recognised forward players, only Jota is outperforming his Expected Assists and Goals, by 0.1 per 90m.
The other out performers are defensive players with low volumes in any case.
All the other attacking players (including Christie and Edouard who are not included) are not achieving the assists and goals the chances created suggests they should.
Rogic and Turnbull, who have been regulars, are 0.16 and 0.27 respectively under their expected output. This equates to 9.6 and 16.2 assists and goals respectively!
This chart also serves to show the power of perception versus underlying performance.
Jota has, rightly, been lauded and his case is helped by being the only over performing forward.
Johnston has been heavily criticised and I have never seen such a gap between expected and actual output. He has 1 assist for 0.16 Scoring Contributions per 90m, but the shots he has taken and passes provided would be expected to yield 1.0 assist / goal per 90m! If he was achieving that he would be behind only Furuhashi!
What would be our perception then?
Player Performance
Here are the players listed by Expected Scoring Contribution per 90m:

Why is there such a disparity?
There won’t be one reason.
Player familiarity. Small details like passing to the players preferred foot. Or learning the runs, the speed, the angles, players like to take up. All can be fractionally out until understanding and cohesion improves amongst this forming group. This will improve with time.
The likes of Furuhashi, Abada and Jota are probably within tolerance for “normal” variance.
Pure luck will be a huge contributor – can we expect to see a few spozzy deflected goals in January??
Shot choice. Rogic, for example, is taking more shots from inside the box than ever before, and most of his shots are central. Problem is that many are blocked (51%). Slight adjustments to shooting decisions may help here.
In Johnston’s case the disparity is so huge I can’t help think that the quality of the final execution must be a factor.
It is the likes of Turnbull, Rogic, Juranovic and Johnston I’d look to improve their shot selection to see if that makes them “luckier”!