Arsenal boss Arsene Wenger has just told BT Sport that starting Alexandre Lacazette is a "little bit of a risk".

"Danny Welbeck has a back problem so it's an easy decision," adds Wenger, who confirms David Ospina sprained his ankle in training yesterday.

On the game, he says: "It is an opportunity but it's a bit tricky when you play the first game at home to find the balance between going forward and defending.

"CSKA Moscow won in Lyon and have had some good results away from home. To win we're going to have to be at our best."

BBC Radio 5 live

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Former Arsenal full-back Lauren has been speaking to BBC Radio 5 live about the Gunners' season.

“This is the most important game of the season. If the team manages to win tonight, we have a big chance of winning the competition.

“If you see the display they did against AC Milan away from home - if the team play with that kind of display, then they’ve got a big chance to win it.”

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Arsenal's defenders could face a different kind of challenge today - CSKA Moscow striker Pontus Wernbloom has spent most of his career as a defensive midfielder.

The 31-year-old Swede has moved up front this season and has banged six goals in 12 appearances in that position.

That stat is from whoscored.com - I don't watch as much Russian Premier League football as I'd like to - so I'm going to have to trust them on that...

James: Tonight is game 1/5 that determines whether our season is a complete failure or actually a bit better than last year...hoping for a win to keep the recovery going.

Image source, Reuters

Arsenal midfielder Granit Xhaka: “I’d have preferred to have the first game away from home, but hopefully we can take a big step towards qualifying at the Emirates.

“We’re looking forward to it and we know it will be tough, because CSKA showed a lot of character to beat Lyon in the last round. They won 3-2 away from home and that’s a good warning for us. We’ll need to remain focused throughout."

Image source, Getty Images

As if to back up my 19:04 BST point, Arsenal and CSKA Moscow have met twice before - in the Champions League group stages in 2006.

Sergei Ignashevich, Vasili and Aleksei Berezutski and Igor Akinfeev all played both games - a 1-0 win for the Russians and a goalless draw.

Image source, Getty Images

Lazio, third favourites to win the tournament, have one of Europe's form strikers.

Ciro Immobile has bagged 36 goals in 39 games this season - six in seven in the Europa League, a goal every 68 minutes.

This is Red Bull Salzburg's first European quarter-final since they were taken over by the energy drink company in 2005.

Austria Salzburg, as they were previously known, reached the 1994 Uefa Cup final, losing to Inter Milan over two legs.

They are unbeaten in 19 European games - and 36 matches in all competitions.

Indeed Atletico are taking things seriously.

This is their starting line-up tonight - Oblak, Juanfran, Savic, Godin, Lucas, Correa, Saul, Gabi, Koke, Griezmann, Costa.

Image source, EPA

Atletico Madrid are the favourites to win the Europa League and, if they take it seriously, probably Arsenal's main threat.

The 2010 and 2012 Europa League winners are in the tournament for the first time since 2013, having finished third in their Champions League group.

This is the only tie between two teams that have previously played in the Europa League quarter-finals (since it was rebranded from the Uefa Cup).

Sporting pair Sebastian Coates and William Carvalho, who it feels like has been linked to Premier League clubs since the Ice Age, return from one-match bans.

Julien Laurens
French football expert on the Euro League Football Show

Image source, Reuters

I just don’t see how Marseille can cope with the intensity that RB Leipzig put in, the way they play, the running.

Steve Mandanda is having a wonderful season, he has been one of Marseille’s best players along with Florian Thauvin.

But I just think that back four of Marseille against Emil Forsberg, Timo Werner, Naby Keita, Bruma and all the attributes Leipzig have going forward, I fear a bit for their defence.

Marseille would do very well to knock them out.

Image source, Getty Images

This is RB Leipzig's first season in European competition. In fact they are the only team in the quarter-finals who have never reached a European final.

Timo Werner has scored six goals in their 10 games so far in the Champions League and Europa League this season.

This is Marseille's 15th game in the competition this season, having come through two rounds of qualifying.

They lost the 1999 and 2004 Uefa Cup finals.

There are three other games tonight, which we will be giving you updates from. For some reason they're all on at 20:05 BST instead of having one or two earlier on as in previous rounds.

Five changes for Arsenal from the side that started the 3-0 win over Stoke last Sunday.

France striker Alexandre Lacazette is making his first start since 30 January following a knee injury, while keeper Petr Cech, defender Laurent Koscielny and midfielders Granit Xhaka and Henrikh Mkhitaryan also return.

Among those making way are keeper David Ospina, who has an ankle injury, and forward Danny Welbeck. Pierre-Emerick Aubameyang is cup tied.

Arsenal: Cech, Bellerin, Mustafi, Koscielny, Monreal, Xhaka, Wilshere, Ramsey, Ozil, Mkhitaryan, Lacazette.

CSKA Moscow name on-loan Leicester City forward Ahmed Musa in their starting line-up for their first game against Arsenal for 12 years.

Musa, 25, started 2018 playing in the EFL Trophy against Oldham Athletic for Leicester's under-21 side.

Pontus Wernbloom and Bibras Natkho are one booking away from missing the return leg next Thursday.

CSKA Moscow: Akinfeev, A Berezutski, Ignashevich, V Berezutski, Kuchaev, Golovin, Natcho, Dzagoev, Schennikov, Musa, Wernbloom.

One thing CSKA Moscow do not lack is experience at the back.

Captain Sergei Ignashevich, 38, and 35-year-old twins Vasili and Aleksei Berezutski - their back three tonight - have been playing together for 14 years now for club and country.

Behind them, 31-year-old keeper Igor Akinfeev has been there for a decade and a half too.

Between the four they have played 2,021 times for CSKA (according to Transfermarkt) and have won 383 caps.

I hope CSKA's scouts in the early 2000s got a good bonus.

Image source, EPA

Arsenal striker Alexandre Lacazette came on - and scored - against Stoke at the weekend - his first appearance since 10 February following a knee injury.

The £46.5m summer signing has scored 10 goals in 30 games since his move from Lyon.

"It's good to have him back because it gives us different opportunities," boss Arsene Wenger said. "Danny Welbeck is more a guy who goes behind, whereas Lacazette is more combination play so to have both options is important.

"I realise now when I see him in training that he was not himself for a while.

"It was not dramatically different before. He was a good player. But I think in the last seven or eight games he played, he was not completely free with his knee."

Arsenal goalkeeper Petr Cech returns from injury to start in goal as the Gunners name a strong team.

David Ospina, who has been their Europa League keeper this season, has an ankle injury.

Striker Alexandre Lacazette makes his first start since January after an injury.

Image source, Arsenal on Twitter

Still waiting for Arsenal's line-up to be announced but here's CSKA Moscow's - Premier League fans might recognise striker Ahmed Musa, who is on loan from Leicester City.

Image source, CSKA Moscow on Twitter

Image source, Getty Images

Arsenal playmaker Henrikh Mkhitaryan scored against CSKA Moscow earlier this season - for Manchester United in a 4-1 Champions League win.

The Armenia international said: "They are a very good team. They have changed a few players and if they are in the quarter-final it means they are very good opponents and there are no easy games to play in that stage.

"We are going to face a very good team with very good experience. Everybody knows that the defensive line with the Ignashevich brothers, they are more than 35 years old and of course they can help them to play better and be more compact in defence."

Arsenal manager Arsene Wenger says he would be happier if the Gunners had been away in the first leg - as they were in the last two rounds against Ostersund and AC Milan.

“When you play at home in the first leg, you don’t know exactly what you have to achieve," he said.

"Usually when you play the second game at home, you know exactly what kind of result you need and that’s not the case in the first.

"You’re a bit more in a situation where you know you have to do both things well - defend and attack well - without knowing exactly what will be needed to qualify."

With Anglo-Russian relations a bit frosty at the moment for political reasons, there aren't likely to be many CSKA fans at today's game.

About 500 Russian fans are expected to attend - although media reports say some of those have not travelled.

Gunners boss Arsene Wenger says: "Diplomatic relations between England and Russia at the moment are a bit complicated. I just hope it won’t affect both ties and that it will not affect the supporters. Nor for the Russian people who come over here and not for English people who want to travel there."

Russia's deputy sports minister has told CSKA fans to stay out of trouble tonight, report news agency Tass., external