More from Celtic manager Martin O'Neill: "It's a huge frustration, obviously, but it's also psychologically quite damning as well.

"Just when you've fought your way back into the game and you think, well if you can't with the minute the fourth official puts up, at least defend it properly and we didn't do that. That was really disappointing.

"It's not the start we wanted. We have seven games in which to try and get some points on the board. Really need to concentrate now on Sunday [against Rangers].

"Tonight was I think a European lesson for us in many aspects. We'll get ourselves together. We need to re-energise ourselves as much as anything else.

"When we have decent possession of the ball, just don't give it away. But also I think taking a few risks as well too - risks in the proper areas of the field."

Image source, SNS

Celtic manager Martin O'Neill: "Well, we're naturally disappointed getting beaten. We started off very, very brightly. We had a number of balls that were flashed across the goal and no-one there to put the ball in the net for us.

"They're first attempt, proper attempt, really, on goal yielded a goal for them. We come back into the game, got the equaliser just before half-time and then conceded a really poor goal.

"We're hit on the break for the third goal. While we had a number of balls flashed across the box even in the last 20 minutes, we didn't get there to the front post a number of times that could've kept it alive and we're beaten in the game."

Image source, SNS

Quotes from Martin O'Neill coming up next.

It's only fair to point out the same Celtic management team stepped into a binfire twice last season and put it out on both occassions to deliver knockout European football and a league and cup double.

They came up with solutions then, and will need to do so now.

James McFadden
Former Scotland forward on BBC Sportsound

The shape hasn't changed. They still line-up in a 4-3-3, a variation of it.

I can see a lack of confidence, absolutely. I can see a lack of urgency and intensity.

At times it was slow and ponderous and laboured. I don't think they look tired or unfit. I just don't think they play with enough tempo in their game. It's all in front of Ferencvaros, there's nothing in behind.

Camilo Duran, when the ball came up to him, didn't stick. Kasper Hogh comes on alongside him, when the ball came up to him, it didn't stick. When it comes up, it's a basic to be able to control the ball and find a team-mate.

Too many wayward passes, too many safe passes, which brings a bit of tension and then you don't see a team playing with that freedom.

Image source, SNS

Stiliyan Petrov
Former Celtic midfielder on TNT Sports

When you have your centre-backs making more passes than your midfielders, you can't dominate.

Tonight, Celtic were playing safe. When did Celtic start playing with fear?

Celtic captain Callum McGregor tells TNT Sports: "[It was] Tough. They scored at good times. It's a sore one but we have to stick together now.

"It's a little bit broken, a little bit nervy, but we have to fight our way through this. The only way through it is hard work.

"It's a tough period. You can see how quickly it comes down on top of you. It's a relatively new group, so we have to learn. You don't get much leeway.

"The ultimate test at the weekend is that we have to win the game. It's about staying together, putting one foot in front of another and we just need another bit of luck."

Image source, SNS

The stats are not the most damning, but another 14 shots conceded for Celtic.

Captain Callum McGregor has said their performances are a bit "broken" and "nervy". More from him shortly.

Image source, SNS

Let's hear from you, Celtic fans.

Why is the team struggling in the big games against comparable opponents?

Stiliyan Petrov
Former Celtic midfielder on TNT Sports

A disappointing performance and a disappointing result.

There was no reaction. Celtic were too safe, they were scared to play. The players that can make a difference don't get the ball in the right areas.

Martin O'Neill has a lot of work to do before the weekend.

Martin Dowden
BBC Sport Scotland at Celtic Park

Celtic tried hard to find a way back into this but at this level, they can barely expect to win given the errors and defending on show.

Bright moments were completely overshadowed by familiar frailities.

It cost them in Champions League qualifying and last week against Rangers. Away to Benfica in their next Europa League fixture, it may well again unless something big changes.

The answers don't seem obvious with scrutiny intensifying over selections, signings and shape.

A bad week just descended to a terrible one with a result against Rangers on Sunday now vital.

A huge blow for Celtic. There was very little response from Sunday's derby defeat.

Rangers to come at Celtic Park on Sunday. How do they go again?

Image source, SNS

Luke McCowan's shot is now blocked. Camilo Duran and the Ferencvaros goalkeeper collide.

20 seconds left.

Camilo Duran goes down on the edge of the box, was he being held?

The referee doesn't think so. We're into three minutes of added time.

Ferencvaros replacement Jonathan Levi gets booked for diving in the box.

It's flat as a pancake at Celtic Park right now. Plenty have headed for the Gallowgate...

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

Image source, EPA

I don't see them getting the vital second goal to give them hope.

They've got to keep going, they can't give up.

Anthony Ralston is on at right-back for Colby Donovan. After a flurry of attacks and chances, Celtic look to have punched themselves out.

Celtic have Benfica, Marseille, Union Saint-Gilloise, Celta Vigo, and Besiktas to come in the competition, among others.

This game, at home, should be a victory really. It's only going to get tougher.

James McFadden
Former Scotland forward on BBC Sportsound

Again, it's self-inflicted. Liam Scales steps in, plays a pass - I don't know who he's trying to find - straight to Ferencvaros. It allows them to go and get the ball forward and break at pace.

It can't just be 'play it forward to no-one'.