Former Chelsea player Miroslav Stoch delivers two crosses from the left - first from a free-kick, the second from the clearance - but, again, the Blues defence clear easily.

This match has yet to catch fire, or a flame...

Goal in London....

Image source, Getty Images

Mark Galloway: This is Arsenal's best starting XI all season. May not be good enough but at least the shape is better.

Ross Barkley goes down clutching his shin, seemingly in agony, following the challenge of Michael Ngadeu-Ngadjui.

He gets up a few seconds later.

Vladimir Coufal then gets a bit of his head to a cross from the left which fails to trouble keeper Kepa Arrizabalaga or his goal.

Arsenal win another corner - this time Kalidou Koulibaly concedes under pressure from Alexandre Lacazette.

The defender is a little frustrated with himself - methinks he thought he should have conceded a throw-in at worst.

Thankfully for him, the resulting corner is rubbish.

Image source, AFP

Big news from Spain where Valencia have taken the lead in the all-La Liga tie away to Villarreal after Premier League referee Michael Oliver awarded the visitors an early penalty.

Former Paris St-Germain winger Goncalo Guedes, who was brought down by Santiago Caseres, fires home after Daniel Parejo's spot kick is kept out by Andres Fernandez.

Over in Prague, Ross Barkley has the Blues' first effort - a 20-yarder that creeps a few feet over the bar.

That chance comes a few moments after Simon Deli headed a couple of feet wide for the home side.

Image source, Getty Images

First Aaron Ramsey sees his low shot blocked by the brilliant Napoli defender who repeats the trick to prevent Ainsley Maitland-Niles' effort causing damage.

Value goes up.

Image source, Getty Images

The Gunners corner comes to nothing as does the follow up.

But the home side retain possession. It's been a good start for the man they call, 'The King of the Europa League*' Unai Emery.

*They don't call him that

Image source, Reuters

Slavia have started on the front foot, although have yet to test the Blues defence.

Image source, Reuters

Pierre-Emerick Aubameyang stretches his legs for the first time which forces Napoli's Nikola Maksimovic to make a slightly panicked clearance from his own area.

The Gunners now have a corner...

Image source, Reuters

We are under way at the Emirates and the Eden Arena.

Arsenal make five changes from the side who lost 1-0 to Everton. Pierre-Emerick Aubameyang has recovered from a recent illness and partners Alexandre Lacazette up front.

Defender Laurent Koscielny is back from a foot injury and starts, as do midfielders Lucas Torreira and Aaron Ramsey. Petr Cech is back in goal from Bernd Leno.

Mesut Ozil keeps his place, but Henrikh Mkhitaryan drops to the bench.

Napoli make three changes to the side who drew 1-1 with Genoa. Lorenzo Insigne is back in the starting line-up after a thigh injury, with Alex Meret starting in goal and Mario Rui back in the team.

Goalkeeper David Ospina is on the bench against his parent club. No rules stopping loanees playing against their club in Europe.

Arsenal: Cech, Sokratis, Koscielny, Monreal, Maitland-Niles, Torreira, Ramsey, Kolasinac, Ozil, Lacazette, Aubameyang.

Napoli: Meret, Hysaj, Maksimovic, Koulibaly, Mario Rui, Callejon, Allan, Fabian Ruiz, Zielinski, Insigne, Mertens.

Image source, .

The teams are out at the Emirates and the Eden Arena.

Cue the famous Europa League music.

Image source, re

Slavia Prague have made five changes to the side that thrashed Dukla in the Czech league in their last match.

Slavia Prague: Kolar, Coufal, Olayinka, Ngadeu­-Ngadjui, Stoch, Boril, Deli, Sevcik, Traore, Masopust, Kral

Subs: Kovar, Zmrhal, Husbauer, Van Buren, Kudela, Skoda, Frydrych

Maurizio Sarri has made seven changes to his Chelsea side that beat West Ham in their last outing.

Eden Hazard drops to the bench while Olivier Giroud returns to the starting line up to maintain his run in the team on European nights.

Chelsea: Kepa, Azpilicueta, Rudiger, Christensen, Alonso, Jorginho, Barkley, Kovacic, Pedro, Willian, Giroud

Subs: Caballero, Kante, Higuain, Hazard, Loftus-Cheek, Zappacosta, Luiz

Image source, BBC Sport

Image source, Getty Images

You might or might not know that Slavia Prague's team features former Chelsea player Miroslav Stoch, who played for the Blues between 2006 and 2010 - he's only 29!!

Anyway, he's a great Pointless answer because he only made four appearances for the Blues.

Here is what he has had to say:

"I have very nice memories and I am a lifelong Chelsea fan.

"I have a Chelsea shirt collection from my time at the club, for example from Drogba, Lampard and Terry."

Will that be on an auction site soon?

Image source, EPA

Napoli boss Carlo Ancelotti has a CV that would rival someone with a really good CV. He has won league titles in four different countries, collected three Champions League honours and helped Juventus win the 1999 Intertoto Cup no less.

He also led Bayern Munich to a two-leg 10-2 beating of the Gunners in 2017.

The affable Italian said of that Champions League last-16 tie: "If I say I forgot it is not true.

"I didn't forget this but each game is a different story, imagine every season different clubs, different manager so it will a totally different story.

"That game with Bayern is only a good memory."

But what a memory eh?

kolawolevictor: Predicted an all English final, but arsenal have got the experience in Emery, so definitely Arsenal