Celtic’s last act in the Champions League proper was an own goal. Apt, in a way, since the club seems like it has been scoring them ever since in its attempts to return to European football’s promised land.

It was Jozo Simunovic who found the back of his own net against Anderlecht on December 5 2017; many feel it has been Messrs Lawwell, Lennon and McKay doing it in the seasons since.

The perennial sight of an underprepared Celtic unable to meet the task of making the group stages reared its head again this month as FC Midtjylland of Denmark added their names to those such as Artmedia Bratislava, Maribor, Ferencvaros and Cluj as undersized doormen denying the Hoops entry to the party.

It’s now been four seasons since Celtic graced the competition. Here, The Celtic Way takes a look at each of those last four qualification failures.

Season 2018-19

Opponent and stage of exit: AEK Athens, third qualifying round

Major ins: Odsonne Edouard (from PSG); Emilio Izaguirre* (from Al-Fayha), Scott Bain (from Dundee); Filip Benkovic* (from Leicester, loan)

* not signed in time to play in decisive qualifier

Major outs: Moussa Dembele* (to Lyon); Stuart Armstrong (to Southampton); Erik Sviatchenko (to FC Midtjylland); Timothy Weah (to PSG, end of loan spell)

* Still at club at time of decisive qualifier

After a relatively serene stroll through the first two qualifying rounds against Armenian side Alashkert (6-0 on aggregate) and Norwegian champions Rosenborg (3-1 on aggregate), Celtic were found lacking when asked to up the pace against AEK Athens.

The Greek Superleague titlists – featuring future Parkhead signing Vasilis Barkas between the sticks – grabbed an away goal in Glasgow despite playing almost half the match with 10 men. In the return leg, AEK flew out the blocks to go 2-0 up in 50 minutes. While Scott Sinclair found the net with 12 minutes left to give his side a chance of an away-goals win, it did not come to fruition.

On the transfers front, Stuart Armstrong had departed for England by that stage of qualification and, while Moussa Dembele was still available and had linked up well with new permanent signing Odsonne Edouard in pre-season, he was edging towards the exit himself and played just half an hour in the second leg after a spell out with thigh problems.

Likewise, while Dedryck Boyata was technically available to manager Brendan Rodgers, the Belgian defender was the subject of interest from Fulham at the time and was thus deemed ‘not ready’ for action and did not feature in either leg.

Defender Filip Benkovic – who enjoyed a standout season until a January ankle injury kept him out for almost 50 days – was not signed until after the tie.

Season 2019-20

Opponent and stage of exit: CFR Cluj, third qualifying round

Major ins: Christopher Jullien (from Toulouse); Boli Bolingoli (from Rapid Vienna); Hatem Abd Elhamed (from Hapoel Be’er Sheva); Jeremie Frimpong* (from Manchester City); Greg Taylor* (from Kilmarnock); Fraser Forster* (from Southampton, loan); Mohamed Elyounoussi* (from Southampton, loan)

* not signed in time to play in decisive qualifier

Major outs: Kieran Tierney (to Arsenal); Emilio Izaguirre (to CD Motagua); Dedryck Boyata (to Hertha BSC); Mikael Lustig (to KAA Gent); Filip Benkovic (Leicester, end of loan)

Again, the team had been sailing along nicely through the first two rounds – wins over Sarajevo (5-2 agg) and Nomme Kalju (7-0 agg) – before they hit an iceberg once more.

It was actually advantage Celtic after leg one as James Forrest secured an away goal in a 1-1 draw. However, Lennon’s men ended up on the wrong end of a seven-goal thriller in Glasgow as Paradise was lost to the Transylvanians in the return.

As well as high-profile departures such as Kieran Tierney and Dedryck Boyata, Celtic were still coming to terms with Brendan Rodgers leaving for Leicester City earlier in the year.

READ MORE: Celtic are now the name on every European team's qualifying wish list - Tony Haggerty

Neil Lennon was now back in the Parkhead dugout and fresh from completing the job Rodgers had left unfinished: the treble treble. A summer recruitment drive brought in several players who would become regulars that season. That said, of the three defenders actually signed up in time for the Cluj tie, only Hatem Elhamed was deemed ready to start both legs. Between them, they cost the club over £11million.

The second leg is notoriously remembered for Lennon’s decision to start Callum McGregor at left-back to accommodate Olivier Ntcham in midfield. McGregor did not hide in his new role; he was both culpable for one of Cluj’s goals and instrumental in setting up James Forrest for one of Celtic’s as the Hoops spent yet another year outside the tent.

Season 2020-21

Opponent and stage of exit: Ferencvaros, second qualifying round.

Major ins: Albian Ajeti (from West Ham); Vasilis Barkas (from AEK Athens); David Turnbull (from Motherwell); Shane Duffy* (from Brighton, loan); Diego Laxalt* (from AC Milan, loan); Mohamed Elyounoussi (from Southampton, loan extended)

* not signed in time to play in decisive qualifier

Major outs: Craig Gordon (out of contract); Jonny Hayes (out of contract); Boli Bolingoli (Istanbul Basaksehir, loan*); Jozo Simunovic (out of contract); Fraser Forster (to Southampton, end of loan)

* still at club at time of decisive qualifier but unavailable after Covid breach

This one-legged tie – which came after a 6-0 demolition of KR Reykjavik in the first round – is infamous for another questionable tactical decision: starting Ryan Christie up front on his own after Odsonne Edouard suffered an injury before kick-off while leaving two strikers (Patryk Klimala and Albian Ajeti) on the bench.

As it was, Christie actually scored Celtic’s goal but the advantage of having the tie at Parkhead – even though it was an empty one – was never fully utilised and defensive lapses which would become a feature of the season led to Ferencvaros’ 75th-minute winner as Elhamed failed to deal with a long ball over the top and Barkas was beaten.

In hindsight not doing more to keep Craig Gordon looks now to be a poor decision. It was presumed at the time Fraser Forster would be on his way back to Glasgow but, when that did not come to pass, Barkas was signed up from 2018 conquerors AEK Athens instead.

Losing the versatile Jonny Hayes might not have significantly weakened the starting XI for most games but it surely hurt the squad as a whole. It is also worth noting that Scott Sinclair departed for Preston in January after almost three-and-a-half years of service.

Ismaila Soro signed in that same window, albeit he would not start to make an impact until much later in the year. Likewise, David Turnbull ultimately ended up the bright spot of Celtic’s shocking 2020-21 campaign but at qualifying time he was not yet at the stage of making the matchday squad.

Season 2021-22

Opponent and stage of exit: FC Midtjylland, second qualifying round

Major ins: Kyogo Furuhashi* (from Vissel Kobe); Carl Starfelt* (from Rubin Kazan); Liel Abada (from Maccabi Petah Tikva); Liam Shaw (from Sheffield Wednesday); Osaze Urhoghide (from Sheffield Wednesday); Boli Bolingoli (from Istanbul Basaksehir, end of loan)

* not signed in time to play in decisive qualifier

Major outs: Kristoffer Ajer (to Brentford); Jack Hendry (to KV Oostende); Scott Brown (end of contract); Diego Laxalt (to AC Milan, end of loan); Mohamed Elyounoussi (to Southampton, end of loan); Jonjoe Kenny (to Everton, end of loan)

And now to Wednesday just past. Another year, another loss. This time under a new manager in Ange Postecoglou as well as a new chief executive in Dominic McKay.

Postecoglou made it clear to his new boss that he needed reinforcements at one of his introductory press conferences. When asked how quickly he required them, he replied "yesterday".

He wasn’t wrong. Undoubtedly in charge of the worst-equipped squad in this list, Postecoglou had no real alternative but to start the likes of Anthony Ralston, Stephen Welsh and Dane Murray for the decisive second leg against FC Midtjylland as those reinforcements he needed “yesterday” still weren’t here or ready six weeks later.

No harm to any of those three, but that is essentially a Colts team backline starting a Champions League qualifier. Add in the shaky goalkeeping situation and there was always the potential for groundhog day to strike again.

READ MORE: Celtic are living through their darkest days since Fergus McCann saved them from catastrophe - Kevin McKenna

In addition, both starting-quality right-backs – Jeremie Frimpong and Elhamed – left in January yet neither has yet been replaced. Centre-back Kristoffer Ajer made his long-expected move south and Carl Starfelt was brought in to shore up the defence – the only problem being he couldn’t play against Midtjylland due to Covid quarantine rules that, frankly, the club already knew about in advance.

Brendan Rodgers faced plenty of questions when he ditched the chance of another treble to start life in Leicester a few months early back in February 2019, but now it might be fair to wonder if he saw the signs of a managed decline in the offing even back then.

So you have to feel for Postecoglou when it comes to the Champions League qualifiers. Made the foreman of this vast rebuilding job, it feels like he’s turned up at a site that was condemned before he even had the chance to get his hard-hat and hi-vis on.