Looks like Warren Gatland has been leading the aerobics classes this week...

Image source, Getty Images

Argentinian rugby journalist Sergio Stuart tells BBC Radio Wales: "I'm very nervous!

"Argentina like to be the underdogs, if the Pumas feel like they are the underdogs, they play better than when they are the favourites.

"I read all the Welsh media [throughout the week] and they said that Wales are going to win this match by 10 points - for me, it's 50/50."

Sam Harris
BBC Newsbeat

They’re looking forward to the quarter-final over at Penarth Rugby Club, in the town where lightning-quick winger Louis Rees-Zammit grew up.

BBC Newsbeat went to catch up with some of their U16s team, like number 8 Jac who doesn’t think he has got the speed to give Rees-Zammit a decent race.

He reckons he is more “Taulupe Faletau speed”.

But the lads are confident about the Argentina game, with Jac saying: “If we can win this game, we’ll go to brand new levels.”

Elliot, who plays scrum half for the side, was happy when he saw the starting XV because “it’s crucial to have Dan Biggar and Liam Williams back in the squad if they want to progress”.

Josh Navidi
Former Wales and British and Irish Lions back row on BBC Radio Wales

Out of all the remaining teams, they [Argentina] have got the worst scrum, we need to be conscious of that.

For me, it's all about the breakdown, the speed of ball that Argentina get is how they get on the front-foot - that's a massive thing for them and that's how they get into the game.

Right then Wales fans, let's start off with an easy one.

Confident of a win?

Thumbs up or down.

Head coach Warren Gatland says Wales are "not ready to go home" as they look to continue their World Cup journey with victory over Argentina.

This is Gatland’s fourth World Cup quarter final with Wales and he has reached the last four twice - in 2011 and in 2019.

Who plays who in the World Cup quarter-finals? (All times BST)

14 October

Wales v Argentina - Stade de Marseille - 16:00

Ireland v New Zealand - Stade de France - 20:00

15 October

England v Fiji - Stade de Marseille - 16:00

France v South Africa - Stade de France - 20:00

There will be live radio and text commentary of all four matches on BBC Radio 5 Live, the BBC Sport website and the BBC Sport app.

James Hook
Former Wales fly-half on BBC Radio Wales

I think it'll be one heck of a battle - like I said earlier, the battle of that breakdown is going to be huge.

It's not just Wales who have reshuffled their back-row following the loss of a key forward.

Pumas flanker Pablo Matera is out of the Word Cup with a knee injury he sustained against Japan last week.

So Argentina have made two changes to the team that edged out Japan 39-27 with Facundo Isa starting at number eight.

Tomas Cubelli replaces Dragons scrum-half Gonzalo Bertranou.

Argentina: Mallia; Boffelli, Cinti, Chocobares, M Carreras; S Carreras, Cubelli; Gallo, Montoya (capt), Gómez Kodela, Petti, Lavanini, Gonzalez, Kremer, Isa.

Replacements: Creevy, Sclavi, Bello, Alemanno, Bruni, Bazan Velez, Sanchez, Moroni.

Image source, Getty Images

Image source, Getty Images

Wales full-back Liam Williams and fly-half Dan Biggar have been passed fit for to face Argentina.

It means Wales have 14 of the starting side that defeated Australia and Fiji in the pool stage.

The exception is the loss of Taulupe Faletau, who has been ruled out of the tournament with a broken arm, sparking a back-row reshuffle.

Flanker Aaron Wainwright moves to number eight, captain Jac Morgan is shifted to blind-side and Tommy Reffell is called in at open-side flanker.

Warren Gatland has opted against naming a specialist six, such as veteran flanker Dan Lydiate, with Christ Tshiunza covering the back row in the replacements.

"We had a healthy debate about bringing in a more traditional number six who is bigger and Dan Lydiate can count himself very unlucky not to be involved. He's done nothing wrong," said Gatland.

"But the breakdown is going to be very competitive and we felt with the way Tommy played with his turnovers, you just want your best players on the pitch."

Morgan's co-captain Dewi Lake is named as a replacement however fly-half Gareth Anscombe misses out with a groin issue.

Wales: L Williams; Rees-Zammit, North, Tompkins, Adams; Biggar, G Davies; G Thomas, Elias, Francis, Rowlands, Beard, Morgan (capt), Reffell, Wainwright.

Replacements: Lake, Domachowski, D Lewis, D Jenkins, Tshiunza, T Williams, Costelow, Dyer.

Image source, Getty Images

Bonjour and welcome to the quarter-finals of the World Cup - kicking off with Wales against Argentina in Marseille.

This is the first meeting between these two nations in a World Cup knock-out match so it's all on the line.

Win and you're heading to Paris for a semi-final next Friday night against either Ireland or New Zealand. Gulp!

Lose and you're out. It's as simple as that.

The sun is shining here over Stade Velodrome, though we're not officially allowed to call it that due to World Cup sponsorship rules.

But who will be basking in the sunshine after the final whistle?

First, let's have a look at the team news.