Thierry Henry better than Luis Suarez? Discuss.

Actually, don't. We'll be here all night. Barcelona, in a pink-tinged kit, bossing the early ball at the Etihad. 

And we are under way across Europe!

Image source, Reuters

It's a proper 'old-school' stadium awaiting Arsenal in Sofia. The sort of away trip that used to have crackly commentary down a phone line. Wonderful. 

Ally McCoist
Former Scotland striker on BBC Radio 5 live

It is vitally important that Manchester City do have a disciplined performance.

By that I mean don't go to ground unless you're 100% certain of winning the ball, don't give the referee a decision to make in terms of yellow cards.

To have any chance of beating a team of this class you need 11 men on the park.

Image source, Getty Images

The Scottish champions have only picked up one point from their three games so far and could go out tonight if they lose and City avoid defeat at home to Barcelona.

Michael McDonald: Celtic will not only go out, but will finish bottom of the group.

KoloKK:#AGermanTeam, external will surely beat Celtic and earn something against City to go through.

Jake Cook: Last time Celtic got a point in Europe they celebrated like they won it. Think the green half of Glasgow would party till 2017 if they get another.

Get involved at #bbcfootball on Twitter or text 81111.

Image source, Getty Images

Lionel Messi splits the lines in the tunnel to embrace Argentina team-mate Pablo Zabaleta, and an opportune mascot breaks away from John Stones to grab a handshake from the great one.

Day. Made. 

Napoli have missed the opportunity to clinch their last 16 place today after drawing 1-1 at Besiktas in today's early game.  Former Chelsea winger Ricardo Quaresma had given the Turkish hosts a 78th-minute lead before Marek Hamsik curled home a fantastic 25-yard effort four minutes later to level.

Image source, EPA

West Brom, Barcelona - basically the same challenge ahead tonight, right?

I jest of course. We are 10 minutes away from finding out how Pep Guardiola goes on against Barcelona tonight.

And to see how Olivier Giroud and Aaron Ramsey fare on their return to the starting Arsenal XI.

And whether Celtic can win on the road in the Champions League for just a second time...

Ally McCoist
Former Scotland striker on BBC Radio 5 live

Image source, Getty Images

To have any chance Manchester City are going to have to defend well and take their chances as they come.

But you look at City and the lads they’ve got up front – they can damage any defence on the planet.

They managed to do something to the West Brom team that none of the other top teams in the country have managed – they’re finding them difficult to beat. I thought City absolutely dismantled them.

Chris Bevan
BBC Sport at Etihad Stadium

Image source, BBC Sport

"Pep Guardiola will be part of our family, always," says Barca fan Gabriel (l). "We will always follow him and wish him success.

"He is definitely not going to win tonight, though. We have won the last five games with City, and we are going to make it six."

Cosmin (r) added: "Pep has not adapted very well to English football yet, but he will - because he is a brilliant manager - better than Jose Mourinho, definitely! I think he is going to do very well with Manchester City - he is going to win the championship with them."

The current Barca front three trump that front three don't they? Even though Ronaldinho was mesmeric on his day...

Image source, Getty Images

Ken Ramirez:  If Man City don't beat Barcelona, we may have to ask ourselves, why did we hire Guardiola for?

Matt Johnson: "Neymar Messi Suarez" Ah yes... as much as we all talk about Eto'o Henry and Ronaldinho...?  

Almost time to get the show on the road.

If you want it there is a separate live page for the Celtic game authored by our friends north of the border. You can access that here.

Image source, Getty Images

Barcelona can wrap up Group C this evening.

They will qualify for the knockout stages with a draw tonight, and can win the group if they win and Borussia Monchengladbach do not beat Celtic. 

Lionel Messi has scored six goals in this Champions League campaign so far; two more than anybody else despite featuring in only two matches and has scored 15 goals in his last 13 Champions League games against English opposition.

Chris Bevan
BBC Sport at Etihad Stadium

"Do we miss Pep Guardiola? Yes, because for us, he is still our hero," says Barca fan Paola, who is in Manchester with her father Ignasi.

"But we have Luis Enrique now, and things are still very good for us. He will beat Guardiola tonight.

"Will Pep win the Premier League this season? Yes, but it depends on the players, not him. Will he win the Champions League with City? No, because Barcelona are going to win it!"

Messi, Neymar, and Suarez We'll be talking about that trio for years and years and years. 

Image source, Reuters

Alan Green
BBC Radio 5 live at the Etihad

I'm concerned about what happens defensively for City tonight. 

Zabaleta trained yesterday and starts tonight, maybe that's a slight risk. Otamendi and Stones haven't looked that great together to me, Kolarov is ageing and Kompany is on the bench.

Guardiola doesn't need me to tell him that he needs to make changes in defence over the next season or two. Any defence is going to have problems against Messi, Neymar and Suarez but especially this group.

Phil McNulty
BBC Sport chief football writer at The Etihad

Literally...a superb fireworks display outside the stadium coincides with the arrival of Barcelona's superstars for their warm up.

A spectacular start to the Champions League festivities - let's hope it continues.

Image source, Rex Features

Richard Wilson: No. But they could get a draw if they stick 10 men in defence.

Olasunbo Babatunde Oduala: Am so certain it's going to be a surprise game to everyone who has written City off. Watch out.

David Carter: The Etihad isn't the fortress it purports to be. It's gonna be another Barca masterclass

Ryan Seaton: Of course there's way, Liverpool have done it plenty of times.  

Keep your thoughts coming at #bbcfootball. 

The most unusual video you'll see today. And one that will make you long for an early 1990s kit. Possibly.

BBC Sport looks back at the history of the inter-league fixture between England and Italy, including the 1991 match between an English Football League side featuring players such as Ian Rush and John Barnes, and a Serie A XI made up of superstars including Marco van Basten and Lothar Matthaus.