Celtic captain Scott Brown conceded the penalty that allowed Cluj to level the game at 3-3 with 10 minutes to play.

The ball struck the arm of the midfielder as he tried to clear a corner to safety.

"He’s misjudged the ball and made a mistake," said Lennon.

"Over 12 years you could probably count the number of mistakes he’s made on one hand. He’s bitterly disappointed but we’re not going to make anyone a scapegoat tonight."

Image source, SNS

More from Neil Lennon on Sportsound, who spoke of the need to lift his players for next week's Europa League play-off. Celtic will be at home for that match, with the return leg in either Moldova or Sweden the following week.

"There’s always a bit of a hangover so we need to get past that, make sure we qualify and take it from there," Lennon said.

"We’ll have to try and get a good run in the Europa League instead. The game’s gone, the players will have plenty regrets tonight. We have to do a lot better. This place should be a fortress and the way we approached the game first-half was not acceptable."

Sorry to pile on the misery, Celtic fans...

After a wafer-thin defensive display from the first-team at Parkhead, Celtic Colts have just been knocked out of the Tunnock's Caramel Wafer Cup. They were beaten on penalties by League One Falkirk.

Being papped out of the Challenge Cup isn't nearly as painful or costly as missing out on Champions League football two years running, mind you.

Celtic fans have been in touch on Twitter. Tweet us your thoughts @BBCSportScot.

Zayne: "Defence still needs fixing. If Cluj can score four goals at home then spend some money Celtic. There are good teams in The Europa League if we do qualify."

Mike: "Neil Lennon, you have to take blame on this one. Wrong decision to play your best playmaker at full back.Then take lead again at 3-2 and still lose."

Sean: "Just have to open up the cheque book and strengthen again before the window closes, and concentrate only on retaining the league title."

Some eyebrows were raised when Lennon named Callum McGregor at left-back tonight, but the Celtic boss says the out-of-position midfielder is not to blame for the result.

"People can point at that but he did set up our equaliser and I thought he had a very good game," Lennon told BBC Scotland. "I don’t think the left side was really the problem tonight.

"We’ve got to work with the players. We’ve got to raise their morale, first of all. We’re going to get a bit of criticism and that’s totally par for the course. We’ve worked really hard to get where we are we’ve basically thrown it away. We’ve got some good defenders but for some reason they wanted to slow the game down."

Celtic manager Neil Lennon on BBC Radio Scotland: "The goals we conceded are crazy. You’ve got to do the basics well – you’ve got to stop crosses, close people down, get your head on things – and it was almost as if we scored and wanted to switch off and control the game.

"In the first half, we were way too passive, way too slow with the tempo, so we gave them a bit of a razz at half-time and we got the right response going 2-1 up. But we needed that two-goal cushion. It’s suicidal the goals we gave away tonight.

"The first goal, we got a warning before that, and we still didn’t stop the cross and the guy’s got across for a run. If you don’t do the basics defensively well enough then at this level you get punished. We’ve let it go. We’ve only ourselves to blame. We had the lead and we let it slip through our own decision-making really."

Neil Lennon is joining the boys on Sportsound. Stand by. We'll bring you his reaction on these pages.

Image source, BBC Sport

Fifteen shots and six corners weren't enough for Celtic to get the job done.

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

So, the story of the night:

Celtic fell behind to Ciprian Deac's well-taken header after Callum McGregor was caught out by the Cluj man's run.

James Forrest finished a cracking team goal to level, before Odsonne Edouard pounced on a defensive error to make it 2-1 Celtic.

Back came Cluj, Scott Brown penalised for hanball from a corner and Billel Omrani slotting from the spot.

Two minutes later, advantage Celtic again. Ryan Christie tapped home after fine work from Edouard.

It looked, at that point, that Celtic had delivered the knock-out blow, but Cluj could not be subdued.

Omrani stunned Parkhead with 10 minutes to play, and with Celtic piling forward, George Tucudean struck the killer punch with virtually the last kick of the game.

Crazy, enthralling, and utterly maddening if you're a Celtic fan.

We'll bring you Neil Lennon's take on it shortly...

Image source, SNS

Participation in the Champions League group stage is worth a heck of a lot of money, as former Celtic striker Chris Sutton acknowledges on Twitter.

Tom English
BBC Scotland's chief sports writer

It's a catastrophic performance, catastrophic result. Celtic defended really, really poorly, they were slack multiple times. This was the night when the defence caught them out.

Celtic got what they deserved, which is nothing. You concede four goals in your own stadium when you limit them to one away from home. It's awful. I'm really shocked.

On a breathless night of European action, here's a wee reminder of the scoring sequence:

Deac, 27'

Forrest, 51'

Edouard, 61'

Omrani, 74' (pen)

Christie, 76'

Omrani, 80'

Tucudean, 90+7'

Image source, SNS

The Fields of Athenry echoes around a forlorn and angry Celtic Park as the fans flood towards the exits.

This was a game Celtic were expected to win. Conceding four goals at home was not in the script.

The pocket of travelling Cluj supporters are going absolutely bananas, serenading their heroes.

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

Celtic have been dumped out of the Champions League qualifiers for the second year running.

Incredibly, unfancied Cluj have rattled four away goals past Neil Lennon's men for a 5-4 aggregate victory.

It's the Europa League for Scotland's champions, who will face either Sheriff Tiraspol of Moldova or Sweden's AIK in the play-off round.

A bitterly, bitterly disappointing evening for Celtic.

Celtic, as they have to, are throwing everyone forward now.

James Forrest wins a corner, but Cluj deal with it and win a goal kick. That might be that...

We're into the final two minutes at Celtic Park. The home side need a hero. They'll have six minutes of stoppage time beyond the 90 to save their Champions League dream.

Callum McGregor tries a shot but it whizzes well wide of the target.

Can they create, and take, one last chance?

Meanwhile, on the touchline, Cluj boss Dan Petrescu is absolutely raging at the hefty time added on.

Final change for Celtic, and it's the little-seen, injury-plagued forward Vakoun Issouf Bayo who comes on for Scott Brown.

Edouard, Griffiths and Bayo all on now. Celtic must score, or they're out of the Champions League.