Andy Townsend
Ex-Republic of Ireland international on BBC Radio 5 live

It has been a really positive start from Arsenal. It has been controlled and measured but they need to keep their discipline where the opposition have lost theirs.

Image source, Reuters

Another Arsenal chance!

Danny Welbeck is free inside Atletico's penalty area but Jan Oblak saves his side by sticking out a leg.

And another!

Laurent Koscielny gets it horribly wrong as another change goes begging.

Andrew: Don’t think that was a second yellow, nor was that really a sending to the stands for Simeone. Managers can’t display their dissatisfaction these days. Great for Arsenal though

Christopher: Ironic that Arsenal have gained a huge advantage from a poor piece of play

Nii: Looks like the ref is also trying to join the Arsene Wenger farewell cheer squad.

Arsenal are like a swarm of bees.

Atletico's defence is creaking as Danny Welbeck picks up Jack Wilshere unmarked but the midfielder's header is tame and straight at Jan Oblak.

Andy Townsend
Ex-Republic of Ireland international on BBC Radio 5 live

Simeone can't have any complaints because he has stepped onto the pitch and gone out of the boundaries that he is set.

Image source, Reuters

Recap! Atletico Madrid are down to 10 men and boss Diego Simeone has been sent to the stand.

Andy Townsend
Ex-Republic of Ireland international on BBC Radio 5 live

He catches Lacazette on the ankle, but if I'm being honest I sympathise with Vrsaljko. I think it's a bit harsh. It wasn't a full-bloodied tackle where he has gone flying in, but he is a little bit late. You could argue, on a yellow card, does he need to put the challenge in there?

Incredible scenes!

Diego Simeone has now been sent to the stand by French referee Clement Turpin.

He was already furious at Sime Vrsaljko's red card and he reacted angrily after Hector Bellerin's challenge on an Atletico player went unpunished.

Atletico down to 10 men after NINE minutes!

Diego Simeone can't believe it and is waving his arms in the air as Sime Vrsaljko sees yellow for the second time after a nasty challenge on Alexandre Lacazette.

Vrsaljko is furious but surely it's the right decision.

Advantage Arsenal!

Image source, AFP

Atletico's post is rocking!

A sublime pass by Danny Welbeck finds Alexandre Lacazette who opens up his body and smashes a volley against the outside of the post.

Moments later Nacho Monreal with another good delivery and Lacazette is there again heading straight at Jan Oblak.

Arsenal should be ahead.

Superb cross by Hector Bellerin and Atletico's defence is on red alert.

All the early attacks coming from the home side. Tidy start by Arsenal.

Bradley: I'm a Liverpool fan and I can see Arsenal winning this tonight because Wenger has announced his exit. This will really boost the atmosphere at the Emirates, and they've got to win it for Wenger

Seventy-five seconds and we have the first yellow card of the match!

Šime Vrsaljko hacks at Jack Wilshere's ankles as he threatens to power through and the French referee immediately reaches for his pocket.

Image source, Getty Images

Arsenal, Arsenal, Arsenal roar the home fans...

Cracking atmosphere.

We're under way.

Raphael Honigstein
BBC Radio 5 live's Euro Leagues Football Show

I think this is the final, or should have been the final in terms of the two strongest teams left. The fact it’s over two legs doesn’t work in Arsenal’s favour – you have seen the European know-how from Atletico in the last few years.

They have consistently knocked out better teams because they are almost a machine built for European football. They don’t concede and they need one chance to score two goals.

You think it’s a horrible match-up for Arsenal as they’re the opposite.

Listen to the show here.

Image source, Getty Images

Emily: Good team! Hope we win for Wenger! COYG

Joe: Love Torres, stunning player and top class man! As an Arsenal fan, hope he comes on a flops

No empty seats tonight!

Great scenes as thousands of red and silver flags greet Arsenal as they emerge. Arsene Wenger, smartly dressed as usual, waves to the crowd.

There's a huge roar around the ground.

Image source, Reuters

He's back. But he is on the bench.

Diego Costa scored three goals in six games playing against Arsenal in the blue of Chelsea, as well as generally rubbing the Gunners defence up the wrong way.

Instead it is Kevin Gameiro and Antoine Griezmann up front for an Atletico Madrid side that are led by Uruguayan old-stager Diego Godín.

Arsenal line up with goalkeeper David Ospina between sticks and Mesut Ozil and Danny Welbeck forging the bullets for Alexandre Lacazette up front. Pierre-Emerick Aubameyang is cup-tied.

Arsenal:Ospina, Bellerin, Mustafi, Koscielny, Monreal, Ramsey, Xhaka, Wilshere, Welbeck, Ozil, Lacazette.

Subs:Cech, Holding, Iwobi, Chambers, Maitland-Niles, Kolasinac, Nketiah.

Atletico Madrid:Oblak, Vrsaljko, Gimenez, Godin, Lucas, Correa, Saul, Thomas, Koke, Gameiro, Griezmann.

Subs:Werner, Torres, Gabi, Savic, Costa, Vitolo, Olabe del Amo.

Colourful scenes around the Emirates.

The away end is noisy while thousands of red and silver flags have been handed out in the home areas which are being waved frantically as the teams prepare to emerge from the tunnel.

Five minutes to kick-off...

Image source, Rex Features