When Martin O’Neill took the helm at Celtic just last week, he found himself amidst turbulent conditions but managed to stabilize the situation effectively.

By securing consecutive victories against Falkirk and Rangers, and earning a spot in the Premier Sports Cup final, O’Neill brought much-needed calm and confidence to the domestic scene.

However, even O’Neill’s efforts have limits. In a challenging Europa League encounter with FC Midtjylland, the Danish league leaders dismantled Celtic with ruthless efficiency.

Celtic found themselves trailing 3-0 at halftime, a result of a first half that starkly highlighted the defensive frailties of Tony Ralston and his fellow defenders.

With Midtjylland’s relentless offensive pressure, the match bore a resemblance to last season’s 7-1 Champions League debacle against Borussia Dortmund.

Martin O’Neill was brought back down to earth with a bump after two opening victories

Celtic were simply no match for their hosts in what was a humbling first 45 minutes

Franculino Dju grabbed his side’s third goal of the first half with a clinical strike

Fortunately, Celtic managed to avert a similar catastrophe. They eventually stemmed the onslaught and salvaged a late consolation goal when Reo Hatate converted a penalty, earned by Callum Osmand.

Although he played well when coming off the bench, a cruel fate awaited Osmand when he was stretchered off in the closing stages after pulling up with a hamstring problem.

This was a reality check for Celtic, the sort of night that will have supporters demanding the search for a new manager is now accelerated.

The week began with O’Neill having to make a mad dash back to London to collect his passport. There must have been times last night when he wished he hadn’t bothered.

They were battered by Midtjylland and, while nobody will hold the 73-year-old Northern Irishman personally responsible, it was hard to avoid the feeling the bubble has burst.

Celtic are not out of the Europa League yet. But with games to come against Feyenoord, Roma, Bologna and FC Utrecht, it’s a long, long way back from here.

They now require the sort of miracle that few would be prepared to believe in. Even O’Neill would surely concede that they are living on a prayer when it comes to their European hopes.

The interim boss made two changes on the back of the victory over Rangers at Hampend last Sunday, with Kieran Tierney and James Forrest coming in to replace Marcelo Saracchi and Daizen Maeda.

After scoring three goals in his previous two matches, Johnny Kenny was retained up front just a few days after he and Osmand were told they can ‘conquer the world’ by Celtic captain Callum McGregor.

Probably the best team in all of Scandinavia at the moment, Midtjylland came into this with their own plans of world domination. Or, at the very least, of ruling Europe.

Formerly of Hearts once upon a time as a player, Mike Tullberg has swiftly made his mark with the Danes since taking charge in September.

Flying high at the top of the table, both domestically and in the Europa League, they came into this match brimming with confidence and hadn’t lost at home in 17 matches in a run stretching back to late March.

Celtic had a couple of early sights at goal, most notably when Benjamin Nygren let fly from the edge of the box, but it wasn’t long before the home side settled into a slick rhythm.

Midtjylland’s front three of Dario Osorio, Mikel Gogorza and Franculino were combining nicely and interchanging in a manner that troubled the visitors.

O’Neill saw his side make more of a game of it in the second half, pulling a goal back

Their dominance should have been rewarded when skipper Mads Bech met a wonderfully flighted free-kick from the left. He skewed his shot when he ought to have burst the net.

That should have served as a warning to Celtic with around quarter of an hour played. Alas, it was one they failed to heed.

The capitulation started on 33 minutes when Gogorza got into the left channel inside the box and dinked a ball over to the far post for centre-back Martin Erlic to head beyond Kasper Schmeichel.

The defending from Ralston was awful. He failed to get tight or apply any pressure in his efforts to stop the cross.

It was 2-0 just 90 seconds later and, once again, Ralston was at fault along with Arne Engels. Between them, they allowed Gogorza to cut inside from the left before he fired into Schmeichel’s far corner.

It is often said of Ralston, both with Celtic and Scotland, that he’s a steady performer who doesn’t let anyone down. Plainly, that’s nonsense.

Up against opposition of any notable ability, he is routinely found out and exposed. It was obvious how Midtjylland and Gogorza preyed on the Celtic right-back.

Midtjylland made it 3-0 on 41 minutes when a long throw found its way to Franculino just beyond the far post. Celtic didn’t close him down anywhere near quickly enough and he curled a left-foot shot past Schmeichel.

It was Franculino’s 18th goal of the season. A 21-year-old striker from Guinea-Bissau, and signed from the Benfica youth ranks, he epitomises Midtjylland’s much-vaunted, data-led recruitment policy.

He will almost certainly be sold for a handsome profit in years to come. By the time he was subbed off just before the hour, Celtic were glad to see the back of him.

Reo Hatate made it 3-1 from the penalty spot but Celtic had been thoroughly outclassed

O’Neill made two changes of his own at half-time, with Maeda and Osmand coming on to replace Kenny and Forrest in the forward line.

By that stage, however, it was really just an exercise in damage limitation for the Parkhead side. The novelty factor of O’Neill being in charge had well and truly worn off.

He bought the board some time with the recent wins over Falkirk and Rangers, but nights and performances such as this will see supporters demand that the search for a new manager picks up pace.

Knowing that the job was done, and knowing that they still had another few gears if required, Midtjylland took their foot off the gas.

Celtic scored a consolation when the lively Osmand won a penalty on 78 minutes, with fellow substitute Hatate burying the spot-kick.

That was about as good as it got for the Scottish champions.

The sobering sight of young Osmand later being stretchered off just summed up a dismal evening for Celtic and O’Neill in Denmark.