We often mix and match data for these pieces using the available sources – The Celtic Way kindly provide StatsBomb access, I have my own extensive datasets, and The Analyst, FBRef, Transfermarkt, FotMob and Sofascore are very useful public data sources.

What you will notice is the differences between the sources even in something as simple as completed passes. This probably doesn’t matter to those seeking a high-level overview of trends but does to an anal analyst.

Which is all precursor to the exercise here comparing how Celtic are performing this season versus last. For comparing performance, it is clearly optimal to use the same data source(s).

So, for this exercise, StatsBomb provide some lovely out the box radars.

This piece will cover defending.

Defending

Celtic Way:

At first glance there isn’t much difference. Which is as expected given it is largely the same set of players and fundamentally the philosophy under Brendan Rodgers is not that different than under Ange Postecoglou:

4-3-3 basic shape, 4-4-2 out of possession, high defensive line, press aggressively out of possession, maintain ball control, play forward quickly where possible, get midfielders into the box, invert full backs when appropriate and guard against counter attacks.

It is subtleties within this framework that are of interest. xG conceded is up and the major disparity from the 2022-23 season. 

My feeling is that this is a combination of new manager and slightly different approach taking time to bed in with injuries. 

The defensive areas have been the most impacted by injury. For nearly two seasons Carl Starfelt and Cameron Carter-Vickers were undisputed first picks at centre back.

This season there have been six different combinations at centre back. Carter-Vickers and Liam Scales have appeared together 14 times in 29 matches, less than 50 per cent of the available fixtures. The next most common starting alignment is Scales and Gustaf Lagerbielke with six.

READ MORE: How Celtic beat St Mirren with speed, precision and style

In 11 matches one of the centre-backs has been subbed off. Normally, the centre-backs are not removed from play. The five subs are usually reserved for freshening up the more dynamic attacking players.

Add in a clearly declining Joe Hart – 32nd out of 32 goalkeepers in the Champions League group stages ranked by goals saved over average.

But, despite this, the xG conceded was over one per game early on and is now 0.77 and trending downwards.

Also concerning is that the average quality of shot from the opposition has risen from 0.08 xG per shot to 0.10.

This may not seem much, but over a 38-match league campaign this is an estimated 5.8 extra goals conceded. Celtic are also giving up more shots (7.58 compared to 6.82).

Again, both are trending in the right direction for the Champions as personnel and system settle.

The other differential of note is firstly the average defensive distance. This has increased from 48.72 to 49.98 metres.

Celtic are setting up the defensive line even higher than under Postecoglou’s famously aggressive line. This is undoubtedly a risk when Carter-Vickers and Starfelt are not present.

Carter-Vickers anticipates well whilst Starfelt possessed great recovery speed. If Carter-Vickers is out long term with hamstring issues, will this deepen somewhat is Scales and Maik Nawrocki, neither fleet of foot, are first picks?

Finally, the passes per defensive action have regressed from 5.90 to 6.48. This means that the number of passes the opposition complete per Celtic defensive action has increased by 0.58 per game. It is a proxy for pressing effectiveness.

This is the lowest in the league still. Also, by some distance Celtic have the most counter pressures [pressure applied within five seconds of losing the ball] in the opposition half with the highest level of possession regains resulting.

READ MORE: The proof Celtic's players have bought into Rodgers' style

Celtic are currently playing with a front five of highly effective pressing players – Kyogo Furuhashi, Daizen Maeda, Luis Palma, Matt O’Riley and Paolo Bernardo.

As the squad further settles to Rodgers preferred pressing triggers and strategies, I would expect this to become more effective as the season progresses.

Summary

Celtic’s defending performances have regressed since last season. They are giving up more shots, better quality efforts, more counterattack shots, and more set piece shots.

Pressing effectiveness is also down but remains league leading. Rodgers has implemented subtle changes to Celtic’s defensive strategy.

The team play higher and press more aggressively. Also, rather than the inverted full backs forming a triple lock in midfield to guard against transition, Rodgers wants one of the number eights to fall back and support Callum McGregor.

Even subtle changes take time to become habit. More tellingly, the centre back combinations have been a cavalcade of change with the injury to consistent mainstay Carter-Vickers particularly telling.

Defensive performance data is trending in the right direction despite all this.  With new defensive patterns becoming habits, and with settled defensive personnel, there is no reason Celtic cannot trend further towards last season’s performance levels.