Red and white Arsenal shirts are surrounding Lionel Messi like police closing in on a suspect. Messi is looking to pull the trigger close to the penalty spot, but is crowded out and the danger is averted. Barca are flying now...

Image source, AP

This could become very messy, very quickly, for Arsenal...

Image source, Reuters

Almost a second for Arsenal, who cannot be accused of sitting back and waiting for things to happen.

Once again they fashion space inside the Barca box but Danny Welbeck's strike from a tight angle strikes the woodwork and flies out for a goal kick. 

Xabi Alonso has been replaced by the speedy Kingsley Coman but it's as you were for Bayern in terms of their goal threat. 

The hosts are camped in the Juve half, playing around the opposition box - but the possession is far to slow and the players far too static. 

Juve's back four are ensuring it's a straightforward night for Gianluigi Buffon in goal. 

Image source, Reuters

Hmm - harsh Mark, very harsh...

Danny Mills
Former England defender on BBC Radio 5 live

"The difference between the two sides has been the finishing. This is exceptional. The build-up play was outstanding, Luis Suarez has so much control with his volley. Incredible finish."

End to end stuff now...Arsenal back on the attack. Alexis Sanchez's angled shot is deflected out for a corner, with Danny Welbeck's free header from the set-piece finding an offside Sanchez. Either team could score the next...

It's not often you see Lionel Messi smashing wildly at a shot, usually he caresses the ball like an artist providing the finishing touches to a masterpiece. The Barca talisman smashes one over from the edge of the box, it isn't troubling David Ospina...

Bayern could be further behind. Twice the industrious Alvaro Morata has been through on goal - the first ended in a tame effort at Manuel Neuer and on the second he shot wide after dancing beyond a couple of Bayern defenders in the six-yard box. 

The hosts need to up the ante. Quickly. 

Danny Mills
Former England defender on BBC Radio 5 live

"Danny Welbeck has to score, it was a fantastic ball from goalkeeper David Ospina, a Carlo Cudicini-style side-volley.

"It is a glorious opportunity, suddenly Arsenal would have been back in it and the crowd get nervous. If they had a good centre-forward, they could have had four or five goals against Barcelona."

Oh my...Danny Welbeck is almost clean through after some Route One stuff from the visitors. Jeremy Mathieu's weak header is pounced on by the Arsenal striker, who runs at Barca's last man Javier Mascherano. The Argentine stands up his man brilliantly, lunging in to block when Welbeck tries to hammer one into the top corner from a central position about 15 yards out.

Image source, Getty Images

It's fair to say that Barca haven't been at their fluent best. But they can turn it on at a click of the fingers. Example A...

Neat interplay between Jordi Alba, Lionel Messi and Neymar creates something out of nothing. Neymar's cheeky flick sends Messi clear in the left channel, his low shot towards the far corner pushed out by David Ospina.

Now that Arsenal goal could work two ways - give the Gunners the confidence to press for another or jolt Barca into life. And teams really don't want to make Barca angry...

Jon Spurling: Another pointless away win for #Arsenal, external on the cards? We're brilliant at those... Bayern, Monaco, Milan..... 

James Foster: Might not amount to anything but that was a sumptuous strike from Elneny!

PJ Belfast: As an Arsenal I am sick of the moaners. Arsenal are playing the best team in Europe - anyone will struggle - the other big teams in the Premiership are not outstripping Arsenal in this strange year. Get off Arsene's back you are helping no one. 

Danny Mills
Former England defender on BBC Radio 5 live

Image source, Reuters

"If you hit the target, it goes in. It is a great finish from Mohamed Elneny, the goalkeeper had no chance.

"If Arsenal hadn't conceded that goal in the first half, they would still be in with a chance."

Image source, AP

I must admit, I've not seen much of Alex Iwobi. But the Gunners teenager, making his first Champions League start, has provided plenty of attacking spark. He jinks into the Barca box again, winning a corner. If Arsenal can only grab a crucial goal to give them hope...

Arsenal race out of the blocks as they search for that fast start they desperately need. Alexis Sanchez's cross from the right is flicked clear, but Arsenal recycle the ball again as they patiently probe for another opening. Alex Iwobi and Francis Coquelin work the ball out right to Hector Bellerin - and his cross also finds a Barca forehead.