Celtic's inverted full-backs aren't hipster chin-stroking - Alan Morrison

He is less wedded to the “how” this is achieved as his history shows - the Australian’s sides have aligned in various formations. However, the overriding outcome has often been the same.

One tactical nuance that has caught the eye has been the deployment of so-called “inverted full-backs”.

The Stein legacy players may get more athletic, faster and fitter, but there is very little new in the realm of football tactics.

Celtic fans who know their history will recall a famous evening in Lisbon when Craig and Gemmell became the unlikely weapons to break down the Inter Milan catenaccio. This smothering combination of man-marking creative talents allied to a low compact block was undone by full-backs coming inside and taking over playmaking duties. Gemmell’s game tying thunderbolt came from his right foot in a central position.

Whilst cynics, a stable of Scottish football, will deride inverted full-backs as some chin-stroking affection of the data-driven hipster, Postecoglou is really channelling his inner Jock Stein!

But what does it all mean?

Inversion in Action

The best way to illustrate is with a real example.

The inverted full-back concept came to life thrillingly for Celtic fans with the opening goal in Jablonec on Europa League Qualification duty.

1. In the 12th minute, left-back Greg Taylor receives the ball in the centre circle – he has inverted, made an inside run, to receive the ball.

What you can see is that there are nine Jablonec green shirts in the frame, all either central or defending their right flank.

What you cannot see is that on the Celtic left, Forrest is now isolated against the 10th – the Czech's right back. The Jablonec right-sided attacker has followed Taylor’s run. To not do so would mean Celtic have an overload centrally which most teams will try and avoid.

2. The impact of Taylors inverted run has been to provide the wide attacker (Forrest) with more space and a 1 v 1 situation - this is a desired outcome of this tactical approach.

Forrest has great options. He has space down the line, to cut in or for a pass in behind the defence.

3. Forrest takes the latter option as Taylor makes an underlapping run from his central starting position.

Because Forrest's pass is in behind the exposed full-back, who is effectively out the game, this forces the right centre-back out, and gaps start to appear in the middle. In essence, the defensive system is crumbling.

4. Two further features of Postecoglou’s preferred approach are then evident. Firstly, Taylor does not thrash a "cross" in. His pass is a cutback, low, something many of us were taught as kids!

Secondly, the opposite winger, Abada, has made a run to the centre of the goal, the optimal place to score. Being on his stronger foot on making this 'out to in' movement, and with the pass being along the ground, he is in prime position for a high probability shot at goal.

A goal does result at the second attempt from Abada, thus robbing Taylor of a deserved assist!

Of course, Celtic will not score with every foray by the full-backs infield, but the advantages the system seeks to create are well illustrated in this example which:

1. Creates potential overloads in a central area.

2. Aims to provide space for the wide attacker to be isolated versus the opponent.

3. Allows the central midfielders to push higher up the pitch thus engaging the opposition midfield and forcing them into decisions on whom to mark.

4. In the event the ball is lost, there should be strength in numbers in the crucial central area on the transition.

Perfecting Inversion

As with any new approach, the timing and context when the decisions are made to invert are crucial and will take time to refine and perfect. Also, and the thorny issue for Celtic, is that you need the right personnel to achieve this.

Guardiola is an obvious modern proponent of this approach. At Bayern Munich, he had Philip Lahm and David Alaba amongst others available to play in this way. Both those players can, and do, play central midfield for their clubs and countries and are by any reckoning high-class players.

Similarly at Manchester City, Guardiola has repurposed central midfielders Fabian Delph and Oleksandr Zinchenko into this role, whilst utilising the very talented and extremely rapid Kyle Walker on the right.

No harm to Anthony Ralston and Greg Taylor but this is likely the only article in which their names are located in close proximity to Lahm!

Celtic have not solved the full-back positions since Lustig and Tierney provided a well-balanced mix of height, long passing and vast experience (Lustig) allied to aggressive defending, box to box attacking and cut back menace (Tierney). Ralston and Taylor are last men standing for Celtic at the minute. No one can fault their work rate or desire to give their all, and as seen above, Taylor is a footballer desperate to improve and develop. Ralston has two great goals to his name this season by popping up in central positions.

But neither are likely to be the long-term answer when playing in this way. 

Downside Risk

There is no football tactic that is a “golden bullet” to beat them all or everyone would be doing it. (Apart from having more money - back to Guardiola again!) The inverted full-back approach has downside risk as all tactics do.

As discussed above, you need the right personnel.

A full-back good enough to play central midfield is hard to find. What can happen is what we witnessed in the opening Postecoglou game at home to Midtjylland. Celtic spent the first 20 minutes penned in their own half as they failed to beat the high press.

Taylor’s body shape in the example above is closed and he cannot see his next forward action nor know how close he is to being closed down. This technical limitation has been evidenced from both current full-backs in the early matches.

Furthermore, neither player is a gifted passer nor quick on their feet to be able to skip away from danger like McGregor does.

As well as getting bogged down against the high press (see also between the 50th and 66th minute vs Jablonec), teams playing this way will surrender the flanks. Whilst it is harder to score from wide, teams facing a Postecoglou side are known to try and get overloads in wide areas. Hearts first goal against Celtic resulted from a 2v1 overload on Ralston allowing Mackay-Steven an unopposed tap in.

Conclusion

Inverting full-backs is not new but has already befuddled some Scottish pundits with some asking what the point is. Celtic’s opener against Jablonec serves as an illustrative example.

However, there are downsides, and most crucially for Celtic, they need the personnel with the right skillset to allow the upsides to come to fruition consistently.