Sunday’s victory over Rangers was notable for the defensive resilience on display but, despite the characterisation of Ange Postecoglou as a reckless attacking idealist, this should not have been a surprise.

Celtic have improved at the back throughout the season under the Australian. Unbeaten for 32 matches across all domestic competitions, with 17 clean sheets and only 19 goals conceded in the league, the Hoops are surpassing many of the key defensive statistics they set over the last few Scottish Premiership campaigns.

They are winning in style - but with quietly effective rearguard numbers and tactics too.

Celtic Way:

On average, a shot allowed by Celtic this season has an expected goals value of 0.07, meaning that 14 shots would need to be conceded before a goal is likely. This is a clear improvement compared to last season and also much better than Rangers’ current 0.10 average, which is the highest in the 2021-22 Scottish Premiership campaign. 

The Hoops only permit their opposition an average of just over four shots from open play per league match. This is fewer than they allowed in each of the last three seasons and, under Postecoglou, Celtic are actually conceding fewer shots as a result of being pressed in their own half and fewer shots where only the goalkeeper is between the shooter and the goal.  

Celtic Way:

In fact, this season Celtic have only allowed a total of seven shots from open play in the Premiership which had an xG value of 0.25 or more. They just aren’t allowing particularly dangerous shots that often. As a means of comparison, the Bhoys have themselves attempted 75 open-play shots with an xG of 0.25 or more this season. 

Celtic Way:

Postecoglou’s Celtic dominate the ball, with an average possession of 69 per cent eclipsing that of the last two seasons, and use a high defensive line coupled with quick short passing orchestrated by Callum McGregor at the base of midfield to pen their opponents in.

The full-backs often invert positionally and provide protection against counter-attacks by reverting the pyramid to create a 2-3-5 shape. The wingers in his 4-3-3 formation pin the opposition in place and force them to cover a large horizontal area. To a large extent this is an attack is the best form of defence style and each of these aspects of Celtic’s gameplan has helped contribute to their impressive defensive numbers. 

Celtic Way:

Without the ball Celtic are quick to foul tactically, surround turnover opportunities in an effective diamond-shaped group of four players and press aggressively. The team only allows their opponents to make 5.52 passes for every defensive action that they make (PPDA). This can be an indication of the intensity of a side’s pressing and is an improvement of each of the three previous Celtic league seasons. 

Against Rangers, the Hoops were especially active with the front three of Jota, Daizen Maeda and Giorgos Giakoumakis each making a huge amount of pressures and counter-pressures. 

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That’s to be expected in a match with less possession than normal but, notably, Celtic are allowing fewer passes, dribbles and carries into their own final third on average than in each of the last three seasons. They’re attempting to stop opponents higher up the pitch with the percentage of pressures and counter-pressures that they attempt in the opposition half much higher than last season. 

Celtic Way:

In fact, this tactical choice is clearly evidenced by the fact that this season 79 per cent of the pressures Celtic exert within five seconds of losing the ball occur in their opponent’s half whereas for Rangers it is only 68 per cent.

Although there is a note of caution to be heeded about Maeda’s susceptibility to being bypassed by smarter ball players, his aggression certainly paid off in Sunday’s victory as he pressed the full-backs effectively.

James Tavernier and Calvin Bassey attempted nine and eight crosses respectively and only completed one each. This was not the only occasion on which Postecoglou has been relatively comfortable with his side conceding balls from wide areas this season. His side faces almost four more crosses per game than Celtic did in the previous two league seasons and this is an indication of the setup funnelling attacks into less dangerous areas. 

Celtic are still conceding goals from set-pieces at a rate similar to last season and a bit worse than the preceding two seasons but the underlying numbers are improving.

Under Postecoglou they allow less than half the xG per corner that they did in 2020-21 and are conceding less in terms of both goals and xG from corners than Rangers are this season. Marking duties appear clearer and individuals such as Carl Starfelt, although still a risk at times in possession, have developed their confidence and defensive fundamentals. 

Celtic Way:

In Autumn 2021, former Celt Charlie Nicholas declared:  “I think Ange thought he would just come in here and his playing style would get him over the line, no problem. But it is not about style, it is about winning."

In terms of domestic competition, Postecoglou is winning - and he is doing it with his own style. It's just that his style, and what it can achieve in a defensive sense, needed time and the right players to be fully effective.