Phil McNulty
BBC Sport chief football writer at The Etihad

Manchester City, and indeed The Etihad, have been subdued since that magnificent Barcelona goal - a move of such incisive brilliance and speed it would set any side back.

Barcelona look such a threat on the break that the City fans inside the stadium are fearing the worst every time the visitors sweep forward.

Andy White: Barcelona are too good. I suggest Man City do what we did as kids. Take the ball and go home now before it gets worse.

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Barcelona have played 227 passes to 111 from City in the opening 32 minutes. Lionel Messi has touched the ball 28 times. Only Samuel Umtiti has seen more ball for the away side so Messi is too involved for City's liking.

Image source, .

Atletico Madrid are drawing 1-1 with Rostov. Antoine Griezmann gave the Spanish side, who will go through if they win, the lead, but Sardar Azmoun has just levelled for the Russians.

And in Eindhoven, Robert Lewandowski - who has hit the woodwork twice - has just equalised from the penalty spot. That's PSV 1-1 Bayern Munich.

Marcus Tongue: If you don't mark the best player in the world, City, he'll score. Knife through butter that run.

Andy White: Barcelona are too good. I suggest Man City do what we did as kids. Take the ball and go home now before it gets worse.

Parth Mehta: Quietest a stadium has ever been in a Champions League game.Man City just not getting that push.

So nearly two for Barcelona as first Andre Gomes, and then Neymar, beat a defender inside the area, but Neymar's shot is eventually blocked superbly by Fernandinho. 

Ben Peterson: I'm aMan Utd fan. Blatant penalty for the foul on Sterling, 1-0 City, totally different game. Refereeing decisions can ruin matches.

Image source, Getty Images

Image source, Getty Images

I prefer to revel in the attacking play rather than criticise the defending too much. That was a great goal.

Can Manchester City stop Barcelona? With counter-attacks like that some of you don't seem to think so..

Rambo rambo: Dangerous, Lethal, Breathtaking. What a counter, so clinical.

Matt Clayton: City were dominant & were carved open far too easy by Barca's counter. 13 seconds from their own box to scoring is not good enough.

Paul Woodhouse: Lovely goal from Messi but why are City leaving that much space in behind?

Jordan Elgott: Good start from City, but nothing to show for it. Unreal counter from Barca. Absolutely brilliant.

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The three geniuses up front for Barca have a nasty streak too - as Neymar kicks out at Rahem Sterling to kill a chance to break away. City well in this game for now. 

Scott Sinclair is so close to giving Celtic the lead with their first real attempt at goal. Just as his former team went behind in Manchester, the winger curls a drive against the inside of the post before goalkeeper Yann Sommer flops on the ball.  

Lionel Messi has scored 16 in his last 14 games against English clubs. I think the TV commentator just said that was his 468th goal for Barcelona.

FOUR-HUNDRED AND SIXTY-EIGHT! Just obscene.

Neymar then flashes a shot just wide from the edge of the area. 

Image source, Getty Images

Ankur Goel: I'm sorry, but that counter attack is not even possible in a video game. Ridiculous stuff from Barca.

Matt: Now that is what you call a classic counter attack.

So Arsenal have got one back now, any predictions for the final scoreline? 

William Concepcion: You see there was nothing to worry about, here we come. Come on you Gunners.

Fleazy: Maybe the gameplan was to add drama by giving them a head start?

Andres Lopez: This could be a goalfest. Defending is pretty much non-existent.

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A fortnight ago Manchester City started well against Barca, had their chances, and got whacked 4-0 with Lionel Messi scoring a treble.

Same again? 

Ally McCoist
Former Scotland striker on BBC Radio 5 live

Outrageous defending from Manchester City.

I cannot believe it, even though it is a wonderful goal from Messi in the end.

Where did the City defence go?

Image source, Getty Images

Celtic have made a decent start in Germany but Craig Gordon has now had to make a very good save to keep the scores at nil each.

You can follow that game in full here.