NEARING pensionable age and on the last leg of a haphazard, globe-trotting managerial career, Ferenc Puskás just wanted his charges to play the game the same way that he had. Fluid, quick and, most importantly, attackers always attacking.

But this wasn’t the Mighty Magyars - the three-time European Cup winner, widely regarded as one of the greatest football players ever, was at South Melbourne FC in suburban Australia after stints in South America, North Africa, Southern Europe and the Middle East - and when Puskás instructed his wingers to stay high up the park it left his full-backs, including a certain Ange Postecoglou, cruelly exposed to counter-attacks. 

Postecoglou was South Melbourne FC’s captain at the time and credits Puskás with influencing him in terms of leadership style and philosophy of play.

Celtic’s manager also admits that, as one of those over-worked full-backs, Puskás’ style of football inspired him to think of tactical methods which would protect his area of the pitch without sacrificing any attacking threat. This, for Postecoglou, was the genesis of inverted full-backs. 

Thirty years on and now, as a manager himself, Postecoglou requires his full-backs to invert, overlap, underlap, counter-press and even score last-minute winners on bitterly cold midweek nights in Dingwall.

Analysing the differing attributes, stats and styles of Greg Taylor, Josip Juranovic and Anthony Ralston we can examine the role under Postecoglou, how each individual interprets it and the way in which it might evolve further during his time in Glasgow.

Celtic Way:

Taylor’s return at left-back after a three-month-long injury lay-off helped Celtic deliver one of their most dominant recent performances away from home when they faced Dundee United.

At Tannadice, the Hoops conceded the lowest expected goals (xG) of any of their Premiership trips this season and created the most, whether home or away, that they had in a single league match since the 6-0 win over St Mirren back in August.

There was no on-ball involvement for Taylor during the move leading to David Turnbull’s goal in Dundee but his positioning clearly shows a benefit of inverted full-backs.

Taylor is high enough to kill off any counter-attack at source and central enough that he can force any long clearance to be played wide, into less dangerous space. All of this helps to provide cover for a midfielder, in this case Turnbull, to make a run into the penalty area and for Celtic to score. 

Celtic Way:

No need for six minutes of injury time to guess how Taylor’s stats look as a result of this changed role. Compared to last season he is completing a significantly higher percentage of his passes, making more than double the number of interceptions and is attempting far fewer dribbles.

His direct involvement in chance creation, shown through open play xG Assisted, is down but his overall role in creativity, evidenced by an increase in xGBuildup from 0.77 per 90 to 1.27 per 90, is up.

This probably suits Taylor - a dependable, diligent player with better than perceived short passing skills and great work-rate but neither the athleticism nor killer instinct needed to be a top threat in the final third. 

Celtic Way:

When asked about being a full-back for Celtic under Postecoglou Taylor remarked; “It is a new way of playing. It is not just the full-back being inside it's [being inverted] at the right times.” 

The fact that each full-back is instructed differently and doesn’t simply come inside always was evident against Hibs in the League Cup final.

It was clear that Taylor had been tasked with inverting to a very significant degree whereas Josip Juranovic’s infield movements were not as frequent or as far towards the opposite flank.

Celtic Way:

Juranovic does have a good understanding of being inside at the right time. He didn’t link up directly with Tom Rogic that often against Dundee United but his inverted positioning allowed the Australian to move into space on the flank and receive passes on the half-turn which paid off to great effect for the stunning opener. 

READ MORE: The numbers behind Celtic's League Cup final triumph

Again, Juranovic’s stats are unlikely to surprise keen observers of Celtic this season. He’s in the 99th percentile for passing completion, xG Buildup and deep progressions of the ball into the final third but wins just a quarter of his aerial challenges and compares poorly with both Taylor and Ralston in terms of the percentage of dribblers he successfully tackles and the xG Assisted he provides from open play.

In fact Juranovic gets dribbled past the 18th most of all players in the league which, given how infrequently Celtic’s opponents have the ball and therefore the relatively limited opportunities opponents have to dribble, is significant.

Perhaps his use at left-back has had an impact on these numbers. Maybe Postecoglou is satisfied with him operating as a fairly unremarkable ball progressing false midfielder. Potentially the bread and butter expectation for an SPFL full-back of heading, tackling and assisting isn’t totally needed within this system?

Celtic Way:

Well, Taylor expanded on the role under Postecoglou stating; “I wouldn't say it is just about full-backs being inside as there is a lot more to it.” 

Enter Ralston with - of every player in the league this season, he has the eighth-highest win percentage for aerial duels, the eighth-highest success rate when tackling dribblers (while making double the amount of tackles of almost everyone with a higher rate) and, with a hugely impressive 0.28 per 90, the second-most xG Assisted per match from open play.

There’s your headers, tackles and assists. Ralston is impact. He’s output.

Celtic Way:

There are downsides to his game. When under pressure he completes just 67 per cent of his passes whereas Taylor makes 87 per cent and Juranovic 83 per cent.

He can also be indecisive about closing down the man in possession on the corner of the box which has led to Celtic conceding goals. However, there’s more subtlety and variation to his game under Postecoglou than might be assumed. 

Celtic Way:

Kyogo’s goal against Hearts was an excellent example of one key element of the 23-year-old’s interpretation of the inverted full-back role.

Ralston’s decision-making, timing, acceleration and controlled crossing makes him skilled at overlapping from central areas. This can be a very difficult movement to defend against even for a team in a well-structured low block. 

Celtic Way:

Another attacking move for a full-back, currently increasing in popularity with possession dominant elite level teams, is the underlap.

Liam Scales, deputising for Taylor on the left, provided an assist with an underlapping run from an inverted full-back position for the opening goal against Ross County recently.

This variation within the same role, even when occupied by backup personnel, shows the differing ways in which manager and player can affect a game even if Postecoglou’s Celtic are likely to always play - in simplistic terms - fluid, quick and with attackers always attacking.

If we can trace from a Puskás-influenced defence-by-stealth tactical idea 30 years ago to today’s role for the Hoops, which tends to bend slightly in interpretation depending on which individual occupies it, what could be the next evolution for Postecoglou at full-back? 

His previous club, Yokohama F Marinos, was of course part of City Football Group and the Australian is likely to have a keen eye on Pep Guardiola’s use of the two-footed Joao Cancelo as an inverted left-back for Manchester City.

Creative penetrative passing from the half-space of the type that Cancelo provides is something that, for all of their fine work, we haven’t really seen from any of Celtic’s full-backs so far this season. 

Celtic Way:

Celtic Way:

Although he’ll probably be deployed further forward at Celtic, likely January arrival Reo Hatate has played as a right-footed left-back and might add that further element to fully round out this very modern position for the Celts.

This week Jurgen Klopp said of Trent Alexander-Arnold:  “We adapt our game to his skills. He obviously plays different positions on the pitch.

"Of course he is still in the right-back position, to defend especially, but then he is a right winger, then he’s an eight, then a six, then as a playmaker. He’s a lot of different things for us.”

Of course, the ultimate dream would be to develop a full-back who, like the Liverpudlian, can do it all.

For now, though, it is a fascinating area of the pitch to watch as each of Postecoglou’s options plays their part - inverting, underlapping, overlapping, creating and scoring.