Are Celtic's Europa League knockout qualification hopes realistic? What the numbers tell us

Following a harrowing European qualification process, which included widespread use of youth players and line-ups barely recognizable to the current first XI, achieving knockout-stage football would be quite the achievement. However, is it realistic?

A topic covered recently was the evolution of Celtic’s playing style in domestic league games under Ange Postecoglou so far this season. The focus will now shift to the four Europa League group stage games to date.

Obviously, the sample size is quite limited but it offers some interesting perspectives as to how Celtic’s “Jenga tower” is holding up versus higher-level competition.

From a broad perspective, Celtic have had a respectable non-penalty xG differential through the first four games:

Here we can see that Celtic have actually been second in the group so far - behind Bayer Leverkusen - in this specific metric. It is worth reiterating the importance of game-state when considering these metrics; both Real Betis and Bayer appeared to “turn it on” for relatively brief periods versus Celtic and then dial down their intensity once they achieved two-goal margins.

Next is a series of scatter plot graphs to try to ascertain various aspects of Celtic’s attacking and defensive performances within the four games, starting with non-penalty xG. A quick reminder that scatter plot graphs are typically set up for the upper right quadrant to represent better outcomes.

Here we can see Celtic as a sort of outlier, with relatively high xG but also a high level conceded. That bottom right quadrant will become familiar.

Now we turn to xG from open play only:

This perspective is quite similar to overall non-penalty xG, while Celtic have done a good job in limiting xG from set-pieces so far and are actually in the upper-right quadrant.

Next up is clear shots, which are defined as those shots taken when only the keeper is between the shot taker and the goal:

Celtic have been one of the best teams so far in creating clear shot opportunities and are right on the edge of the two quadrants, which reflects that clear shots conceded has been about average so far.

Now let us take a look at shots created through counter-attacks and, then, from high pressing:

Celtic fall back into the bottom right quadrant in this regard, with output tilted strongly in favor of attack versus limiting opponents.

The trade-off for high-press shots is one of the least favourable metrics, with Celtic about average in creating while quite poor in conceding.

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This remains a potential red flag for the relative strength of Celtic’s “Jenga tower” at European level, as Postecoglou’s preferred playing style is built upon playing out from the back and creating chances from pressing and counter-pressing.

Here we see pressure and pressure regains so far:

Celtic are close to being in the dreaded bottom-left quadrant for the first time in this review, as pressing actions have been below average, while regains sit about average.

This final scatter plot compares StatsBomb’s aggression metric with passes per defensive action. “Aggression” is defined as the proportion of opponents’ pass receipts that are tackled, fouled, or pressured within two seconds.  

With the caveat once again of a small sample size, various inferences can be drawn from this ensemble of metrics.

Postecolgou continues to extract excellent performance levels out of a squad with significant deficiencies relative to his preferred playing style. Celtic dominated a good Ferencvaros side across the two fixtures, with an aggregate non-penalty xG of 4.23 versus 1.35.

However, cracks have appeared versus the higher-quality opponents. This is where the issues in recruitment have been more exposed, as the nexus of keeper and centre-backs who struggle on the ball at this level have created issues. In addition, what has become a dialled-back press domestically has also struggled for effectiveness at a higher level.

Celtic’s more controlled style of play and performances domestically over the past two months offer an interesting question as they look forward to the remaining two fixtures.

Following strong starts to their domestic campaigns, both Leverkusen and Betis have seen performance levels dip recently. Leverkusen have dropped to fourth in the Bundesliga, but their underlying xG metrics currently rank 12th, while Real Betis are down to fifth in the La Liga table and seventh in xG-related metrics.

Will Celtic decide to try to deploy the more controlled domestic style of play in the two remaining group games, or will we see more back and forth excitement like occurred in the first two rounds of fixtures?

Based upon the above numbers, it may be a matter of choosing which “poison” and hoping that Joe Hart can continue his shot-stopping form so far this season.

With the Europa Conference League already secured, here’s hoping on Thursday we see the equivalent of Hagler-versus-Hearns going toe-to-toe. Both sides can come out swinging and let the strongest jaws win.