As the post-mortem continues following Tuesday's wretched Champions League exit for Celtic, the mind goes back to a telling moment from a few weeks ago.

In the aftermath of the champions' thumping win away at Kilmarnock, post-match footage showcased long-serving star, Callum McGregor, attempting to bring Kasper Hogh and Auston Trusty back down to earth. 'It's only two games', reminded the skipper.

Indeed, quite how things can change, a positive start to the campaign undone by arguably the club's worst-ever night in European competition, shipping five away at LASK to continue this miserable record on the continent.

Luke McCowan had notably notched the 'winner' away at Stuttgart last season, even as the Hoops bowed out of the Europa League tie, but the experienced Scot will want to forget this latest outing in a hurry.

McCowan's dismal LASK display in numbers

There's no need for a pile on, with McCowan likely to be aware more than most that his substitute performance simply wasn't up to scratch, as Celtic's lack of squad depth was laid bare in brutal fashion.

The 28-year-old has already split opinion at Parkhead, but he's always felt like a player who can at least impact a game, particularly off the bench, a dynamic, creative playmaker with the knack for conjuring something out of nothing.

And yet, this was a night where Martin O'Neill's men needed mobility and athleticism instead, the decision to sell Arne Engels so swiftly having come back to bite and then some.

It was men-against-boys stuff after the break, in truth, with McCowan the key culprit following his introduction, left looking lost up against a rampant, physical LASK side.

Any player can have an off day, particularly when thrust into an occasion like that, yet what the former Dundee man proceeded to produce was almost inexcusable, ambling around and so errant in possession.

From just 44 touches, he lost the ball 21 times, damningly recording a lowly 59% pass accuracy rate at a time when Celtic needed someone to retain possession.

It was McCowan's lax error that led to the game's decisive final goal, the diminutive midfielder bullied off the ball all evening, it must be said, having won just four of 14 duels.

That performance epitomised the feeling that Celtic's lack of depth was the real killer in the end - let's hope the failure to qualify doesn't influence recruitment too greatly.

How Celtic can upgrade on McCowan before the deadline

Celtic's zip and vigour had long gone even before the substitutions were made, but at a time when O'Neill needed someone to step up and be counted, the second-half arrivals offered next to nothing following their introductions.

Sebastian Tounekti and McCowan are the two men in the crosshairs most notably, the pair so readily losing possession, leaving Hogh increasingly isolated as the game went on.

Of course, it wasn't Benjamin Nygren's finest night either, having kickstarted the descent into chaos with his slack backpass, but McCowan represented the only natural replacement for him on the bench.

That's a dynamic that needs to change, with a perfect upgrade on the £1m man likely to be found in the form of Ermin Mahmic, with Sky Sports providing the latest on that pursuit.

The report outlined that talks were opened regarding the Slovan Liberec star last week, with the 21-year-old since left out of the Czech side's squads as those negotiations remain ongoing.

Said to be valued at around £8m, the hope will be that such a pursuit wasn't purely dependent on Champions League qualification, with the Hoops surely having plenty to spend regardless after cashing in on the likes of Daizen Maeda and Engels to the tune of £33m.

Mahmic, a fleet-footed, mobile playmaker, wouldn't be the Engels replacement Celtic need, but he would be a genuine rival to Nygren in that number ten berth. More importantly too, his arrival could spell the end for McCowan's muted spell in Glasgow.

The young Bosnian is simply a class above, having notably shone this summer with two goals for his country at the World Cup, while McCowan has barely featured in the Scotland conversation in recent years.

As for last season, the £8m man scored seven and assisted a further three goals in Czechia, boasting an average of 1.3 key passes per game, while creating five 'big chances'.

In McCowan's case, while the left-footer did create six 'big chances', he registered just one goal and assist apiece in the Premiership across 2025/26, averaging just 0.9 key passes per outing.

It's also worth noting what Mahmic offers out of possession too, having averaged 2.2 total duels won per game last term, ahead of McCowan's 1.5 average in green and white.

Yes, you could say the Celtic man was hamstrung by his lack of action, but he did still start 12 league games, making that return of just two goal involvements even more disappointing.

In 87 games in total for the Hoops, he's scored only 12 goals, while in Mahmic's case, he's already up to eight in just 30 appearances for his current side.

Of course, tempting the Austrian-born playmaker to come to Glasgow might be a tougher task without Champions League football in tow, but Tuesday laid bare the reality of just how flawed this squad is at present.