Celtic defender Erik Sviatchenko:

"The confidence is still there but whether it's (finishing third in the group) realistic or not, I don't know. It will depend on the next game."

That next game is a trip to Borussia Monchengladbach, who were so impressive tonight. And let's not forget that was an under-strength side.

Thanks for your company on what has been a very damaging evening for Celtic's European aspirations.

Celtic goalkeeper Craig Gordon: "Their movement was fantastic, which we expected. They are good team and were always going to create chances. 

"It's disappointing to give away the goals we did but we didn't impose ourselves on the game and close them down like we wanted to."

BBC Sportsound pundit Pat Bonner, former Celtic goalkeeper: "There were more than two mistakes in the game.

"Borussia were a better team because they did a lot of things differently to Celtic.

"Celtic were a bit short at the things they have been so good at this season and I'm sure Brendan Rodgers will remind the players of that."

More from Celtic manager Brendan Rodgers:

"The players poured everything into the game against a top side. Scott Brown showed again that he's a top player at this level and so did one or two others. At this level, mistakes get punished and that's our disappointment; gifting them two goals.

"We'll go again tomorrow and get ready for a big weekend."

What next for Celtic? Brendan Rodgers' team won't have any time to feel sorry for themselves since they have a meeting with city rivals Rangers on Sunday.

A place in the League Cup final is up for grabs at Hampden.

Kolo Toure doesn't often play two games in a week, so we might not see him at the weekend.

Celtic can forget about progress in this competition now, if that was ever a target in such a tough group.

To have any chance of finishing third and making the Europa League, they're going to have to beat a Gladbach side who have outclassed them tonight in Germany in a fortnight.

That doesn't seem particularly realistic on the evidence of the last 90 minutes and Celtic's European record on the road makes ghastly reading but you never know...

Celtic manager Brendan Rodgers talking to BT Sports:

"We were beaten by a better team; you can't argue with that.

"They were just sharper and quicker and that's the level we aspire to.

"When a game is going like that you don't want to gift anything and, unfortunately, we gave away two gifts.

"Kolo Toure has been outstanding since he got here and nobody is attaching any blame to him."

Celtic defender Kolo Toure talking to BT Sports: 

"I have to blame myself. It was a simple action to put the ball to the side (for the first goal) but I like to keep the ball in play.

"Over-confident? For the second goal it was the same thing.

"I don't like to make mistakes but mistakes happen. I'm 35 and making a mistake like a 16-year-old."

Image source, SNS

Manchester City finished the game with nine men with David Silva joining goalkeeper Claudio Bravo and Barca's Jeremy Mathieu in being sent off.

A Lionel Messi hat-trick and a Neymar goal give Barca a comfortable win over Pep Guardiola's side.

Image source, Getty Images

Prior to this evening, Celtic had only ever lost three home matches in the Champions League Group phase; twice to Barcelona, and to a Mario Balotelli-inspired AC Milan.

Gladbach, who hadn't won away from home in Europe's top tournament since 1977, were missing a host of first team regulars but were not daunted in the slightest and thoroughly deserved their victory.

Both goals were a mess from a Celtic perspective but there is no question the Germans were superior in every way.

Is that the end of the line for Celtic's European prospects? Brendan Rodgers' side drop to bottom of Group C, with two of their three remaining games away from home and the team still to visit Glasgow? Barcelona...

There's a Borussia substitute waiting to come on and he doesn't look too happy as his team-mates play keep-ball. Bang goes that Champions League bonus.

The agony is nearly over for Celtic as the visitors knock the ball around with a confident swagger.

Another Borussia change as Andre Hahn gets a warm ovation from the boisterous group of visiting fans. Patrick Herrmann is on for the last few minutes.

The visitors make their first change of the evening to eat up some time as the impressive Ibrahima Traore makes way for Nico Schulz.

I think Alasdair might be on to something... It would complete a thoroughly miserable night for the defender.

A reprieve of sorts for City as Barcelona are also reduced to 10 men.

Jeremy Mathieu fouls Raheem Sterling and, already booked, receives his second yellow.

Are Celtic really going to go 90 minutes without seriously testing the visiting goalkeeper? It's looking that way as the Scottish champions huff and puff, with Borussia continuing to snap at their heels with great energy.