In the open air of the Raiffeisen Arena, with bedlam all around, there was nowhere to hide for Celtic or Martin O’Neill.

The Scottish champions had endured one of the darkest nights in their European history.

After going out to Kairat Almaty on penalties last year at this stage of the Champions League play-offs, that is saying something.

Four goals up on aggregate against LASK, O’Neill’s Celtic somehow conspired to implode in a second half with little sign of a response on the way to a 5-4 aggregate loss.

There was no hiding place, and the Celtic manager was frank when put in the spotlight at full-time.

“I’m responsible for this one,” he said.

“Without a doubt. Naturally it took me a long time to get over the Uefa Cup final in 2003 but this was majorly disappointing.

“In the context of things, one was a final which it would have been terrific to win, this was a qualifying game which we should have been able to get through.

“We know that we are a million miles from the finished article. That’s absolutely true. I think we thought that anyway.”

O’Neill was not in charge for that defeat in Kazakhstan a year ago as it triggered the start of the end for Brendan Rodgers’ second spell at Celtic Park.

The current Parkhead boss helped steady Celtic’s ship last term following Rodgers’ exit and again following the Wilfried Nancy saga to guide them to another league title and a Scottish Cup.

This season appeared to get off to a prosperous start until the roof began to cave in over in Austria.

Away from the raw pain of stumbling in such a stark way, the aftermath could be telling for Celtic who now have to not only pick themselves up, but finish off a transfer window without the hefty windfall which would have blown in with the Champions League.

“The qualification for the Champions League is major, it’s major in every aspect,” said O’Neill.

“Financially, for prestige, but we have to pick ourselves up. That’s my responsibility again to do that.

“I think I said last week that if you could qualify for the Champions League there would be players wanting to come on that basis.

“That’s not going to be the case but we’ll see. Tonight we came up well and truly short, particularly in the second half.”

Celtic captain Callum McGregor tells Amazon Prime: “We got what we deserved. We were passive all night. We looked scared to go and win the game.

“I didn’t think we were that good in the first leg either. We scored at good times and got away with it.

“We have to suck it up. We apologise to our supporters and the club because there’s no way we should lose that game.

“It’s as much on the players as everyone else. You can’t look for excuses elsewhere.

“You’ll now see what people are made of. When you play like that you can’t have any excuses whatsoever.

“When you go 1-0 up in the game and it still doesn’t settle you, you can’t have any excuse and that’s on us.

“You fall at a big hurdle and these questions [on whether the squad are ready] are going to be asked. You can’t lose by that margin then look for excuses elsewhere.

“This is what it’s like to play at Celtic. You have to bounce back, you have to show a reaction and that’s what Celtic are all about.”

Former Celtic captain Scott Brown on BBC Radio Scotland: “It was a fantastic start, you go 1-0 up, but that seems like forever ago. Now they’ve crashed out the Champions League and conceded five goals.

“LASK outran Celtic in a couple of areas, the two up front were strong, solid and willing runners.

“LASK deserve to go through with that performance. I feel for the lads because I’ve been in that situation as well.”

Former Celtic manager Neil Lennon on Amazon Prime: “It looked to me as if Celtic were exhausted. Fragile in duels. It only looked like there would be one winner.

“Huge credit to LASK.

“They battered Celtic tonight, physically and on the football side. It could have been more.”

Former Celtic midfielder Stiliyan Petrov: “Everyone [is to blame].

“They are all in it together. A big club like Celtic should be able to hold that out.”