DEFENCE wins championships, they say.
Good thing, then, that Celtic's rearguard is statistically the meanest in the Scottish top-flight, having conceded 17 goals in 27 games.
That total is five better off than nearest rivals Rangers and means Ange Postecoglou's side sit with more wins, more goals scored and fewer goals conceded than Neil Lennon's did at the same stage last season.
But there remains a problem. A niggling issue that, if not quite threatening the heart of Celtic's title challenge, then certainly around the heel area: set-pieces.
Although their overall goals against total is a respectable level, the fact more than half of their concessions have come via set-pieces is cause for concern, as it was last season and arguably even further back than that.
At the other end, too, there is a perception of profligacy when it comes to taking full advantage of offensive set-pieces.
Are those inclinations correct or is there an element of nitpicking at one of the only subpar areas of a team that hasn't been beaten domestically since September 19?
Here, we take a closer look at Celtic's set-piece struggles, how they compare to last season and the common themes among this term's concessions...
A pre-existing condition...
Last season Celtic scored 14 set-piece goals (12.7 xG) from their 153 generated shots from set-pieces (that is direct free-kicks, indirect free-kicks, throw-ins and corners, but not penalties). Their goals scored total was tied with Rangers (11.6 xG, 150 shots) for most in the division.
Defensively, Celtic conceded 12 set-piece goals (9.5 xG) from 99 shots allowed from set-pieces. This total was joint fourth-worst in the league, level with Livingston and better only than Ross County, Kilmarnock and Dundee United. At the opposite end of the rankings, Rangers conceded just one set-piece goal (5.6 xG) from 72 shots allowed.
StatsBomb notes that the 2020-21 league average worked out at 9.6 set-piece goals (9.7 xG) from 122 shots, so Celtic performed above average in scoring from set-pieces, and in generating shots from them, but below average in conceding from them regardless of the fact they were slightly above average in terms of how many shots they allowed from set-pieces in general.
What has changed this season?
We are now more than two-thirds of the way through the league campaign and so have the benefit of a decent sample size to work with. That said, there is an argument even a full season isn't a sufficient length of time but, for what it is worth, here are the comparative numbers so far...
Celtic have scored 10 set-piece goals (11.3 xG) from 148 shots. Their goals scored total sees them sit level with Aberdeen (8.3 xG, 118 shots) while Rangers are again at the head of matters with 12 goals (10.9 xG, 138 shots). Although underperforming in terms of xG, Celtic's uptick in shots per set-piece puts them top of the pile in the division for shots generated from set-pieces at 0.12.
At the other end, Celtic have conceded nine set-piece goals (5.1 xG) from 60 shots allowed. Five of those nine concessions have been headers. Their total is joint second-worst in the league alongside Motherwell and behind Ross County. St Johnstone (8.4 xG, 108 shots) and, in a big reversal from last season, Dundee United (10 xG, 113 shots) have allowed the fewest set-piece goals with just three conceded apiece.
It is worth noting that, so far this campaign, Celtic are actually conceding fewer shots per game than last season (2.2 compared to 2.6) and are ranked as both the team that allows the fewest shots taken per set-piece and the team expected to have conceded the fewest goals from set-pieces in total. The rather large caveat to those numbers is that they have still conceded almost four actual goals more than they "should have" going by the quality of the chances that they have given up.
For reference, StatsBomb has the league average so far this season sitting at 6.9 set-piece goals (7.4 xG) from 96.5 shots so, again, Celtic are performing above average in terms of scoring and generating shots from set-pieces, as well as in allowing shots from them at the other end, but below average in conceding from the shots they do allow.
Corner conundrums: attacking
So that's the overall set-piece data, but let's break it down a bit further by looking at different types of set-pieces starting with both the most productive and most frustrating: corners.
Eight of the Hoops' 10 set-piece goals have come from corners. These are split evenly at four apiece from the right and left but, upon closer inspection, there are very few commonalities in how Celtic have successfully converted their corners.
Without wishing to use the term ‘winging it’, it suffices to say there doesn’t seem to be a whole lot of pre-planned organisation going on. A majority of the corner conversions are better described as profiting from the chaos a set-piece can bring as opposed to producing routine-driven chances. They all count, of course, but the distinction is still there.
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With that in mind, the eight goals can be broken down thusly: one what we'll call 'traditional' corner (Cameron Carter-Vickers' finish from an inswinger against Hibs); two after some semblance of short corner play (Anthony Ralston v Dundee and Giorgos Giakoumakis v Dundee); five 'scrappier' efforts after the initial corner attempt has essentially broken down and the ball has been subsequently flung back in, scored on a rebound or, in the case of Callum McGregor v Aberdeen, been smashed off his backside by an attempted clearance and gone in.
For the record, the other four 'scrappier' goals are as follows: Albian Ajeti v Ross County; Anthony Ralston v Ross County; Jota v Dundee; Reo Hatate v Rangers.
Corner conundrums: defending
Corner concessions are slightly different. All five of Celtic's conceded goals from corners have come in the six-yard area and the common theme running through them is a seeming inability to deal with, and adapt to, teams using initial runners to drag players away from their zones and leave gaps in dangerous areas. Indeed, of the five corner concessions, four were inswingers into the six-yard area in which the opposition sent runners across the front post to clear space.
The odd one out is Lewis Ferguson's header at Pittodrie in October, where Calvin Ramsay delivered an outswinger and Adam Montgomery's goalline defending was ineffective. In all five situations there are question marks over the decisiveness with which the Celtic defenders attempt to win the ball (and not for nothing, but I've watched each incident something like 320 times and still won't commit to saying whether they're meant to be using zonal, man-marking or a weird hybrid of both).
Likewise, each time goalkeeper Joe Hart opts not to even attempt a claim. This is unsurprising given he rarely does so in general, but there are at least two or three instances where a more commanding custodian likely takes control of the situation rather than standing pat as it unfolds a mere couple of yards away. A similar situation occurred in the League Cup final too, although our remit today is Premiership-centric.
Judge all that for yourself, though. Here's the footage of all five corner goals:
Non-corner set-pieces
So far this season, Celtic have not scored a direct free-kick and have netted twice from indirect free-kicks (Anthony Ralston v Hibs and Tom Rogic v Motherwell). The Rogic goal is arguably Celtic's only bonafide 'routine' conversion from any set-piece this season.
They also haven't conceded from a direct free-kick but have done so four times from indirect free-kicks.
The common themes running through these concessions are similar to the issues at corners: a lack of adaptation when teams are clearly clued up and ready to use their own routines (see, for example, Christian Ramirez's goal at Pittodrie) or indecision/lack of aggression when faced with a robust opponent with a bit more nous in competing for the ball (take your pick of John Souttar at Tynecastle or Lewis Ferguson at Pittodrie here).
Again, have a look for yourself at the footage of the four indirect free-kick concessions:
* An in-depth breakdown of Souttar's Hearts winner can be found here
Meanwhile, throw-ins might not be the most glamorous part of the game but with clubs such as Liverpool placing more of an emphasis on how to better utilise them, other sides will catch up eventually.
For now, though, while no team in Scotland quite uses them what you could call innovatively, both Livingston and Dundee have recorded a goal apiece from throw-ins this term while Celtic have neither scored nor conceded as a result of throw-ins but have allowed the highest throw-in xG against (yes, it is a thing!) in the league at 0.88.
There is, however, something to be said for the urgency with which Celtic restart play using a throw-in even if it is not strictly in the realms of 'throw-in coaching'. For one such example, watch David Turnbull's role in Kyogo Furuhashi's magnificent chest finish against Aberdeen at Pittodrie.
Where to now?
How best to sum this up then? Well, that's us around 1,500 words deep and you probably still feel like we've only scratched the surface of this topic.
There's some merit in the argument a bonafide dual-box aerial threat like Christopher Jullien being reintroduced would change things but, in truth, it's not so much that Celtic are giving up glorious chance after glorious chance as it is how they are effectively (or, indeed, ineffectively) defending the ones that they do allow through a combination of communication breakdowns, individual culpability and seemingly questionable training-ground planning.
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One man is unlikely to change that culture, although his presence in the attacking equation undoubtedly offers another option for Postecolgou to consider.
In that sense the calls, from the likes of TCW tactics writer Ross Goodwin among others, for the club to embrace specialist set-piece coaching seems, not only as a knock-on effect from last season but even from this one in isolation, bang on the money.
Celtic, like all elite clubs consistently challenging for trophies, deal in marginal gains. They already possess the best defence in Scotland despite these set-piece struggles so, if they start to treat this particular Achilles heel, there will be very little left for opponents to take aim at.
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