Alan Shearer
Former England striker on BBC One

Messi's numbers are bonkers, not just the goals but the games he has played, because everybody tries to kick him.

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC One

It's everything. People buy tickets just to watch Messi play football. He's such a joy and he's still performing at the highest level.

Pass the ball to Messi, when I played with him, that's all we needed to do.

Image source, .

Tonight is Lionel Messi's 1,000th senior game of football. He has played 778 times for Barcelona, 53 for current side Paris St-Germain and tonight will be his 169th game for Argentina.

If you combine World Cup qualifiers (60) and the World Cup finals (23 after tonight), that makes this his third most played-in competition after La Liga (520) and the Champions League (161).

He is one of only six players to appear at five different World Cups.

In his 999 games to date he has scored 788 goals and made 338 assists.

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC Radio 5 Live

Australia are a strong team defensively. They don't make mistakes and it's going to be difficult for Argentina.

I would expect a similar game to the one against Poland, probably they will sit back, defend compact and tight and they see if they can go and counter attack. Aaron Mooy is a very solid playmaker in midfield.

Set-pieces could be a huge problem for Argentina because they have big players and they look strong on set plays. We need to be careful.

Andy Cryer
BBC Sport in Qatar

I know I've said it before, but this noise is ridiculous...

The song that keeps reverberating around Ahmad bin Ali Stadium is “Muchachos, Ahora Nos Volvimos a Ilusionar” (which translates roughly to “Boys, We Have Our Hopes Up Again”).

Apparently a viral hit with Argentine fans after Lionel Messi stated it was his favourite football song on a TV show and even sung some of it.

It is pretty catchy...

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC Radio 5 Live

I'm confident, after that performance against Poland, the team played well. It's a good chance for Argentina tonight.

We need to go into that game with the right mentality, we need the humility that you always need in those games, because the Asian teams have been playing with so much passion and that never-say-die attitude and that's why it could be a tricky game.

Hopefully Argentina can have a good game and an early goal will be so important today. Hopefully they can put in a good performance and go through to the quarter-finals.

Chris Bevan
BBC Sport at Ahmad Bin Ali Stadium, Qatar

Image source, BBC Sport

There aren't many Australia fans here tonight but it's not hard to spot them - a small pocket of yellow behind one of the goals.

The rest of this stadium is pretty much full of Argentina supporters.

Image source, .

Australia's only win in seven games against Argentina was in their first meeting in 1988. Current Socceroos boss Graham Arnold played in that match.

"No disrespect to Argentina, but it's 11 v 11, and it's 10 blue shirts against 10 yellow shirts, and it's a battle," Arnold said.

"It's a war, and we've got to fight that and make sure that the boys are in great physical shape, great mental shape, they've got great energy, and we go out there and give it all guns blazing."

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC Radio 5 Live

Lionel Messi is a player who has always been hugely important in the knockout stages. I remember in 2014, I know we rely on Messi so much at some point but when you have him in the team, all you want to do is pass the ball to Messi and when he finds them small spaces outside the box, he is always dangerous.

He missed the penalty against Poland and then a good chance inside the box but he is still looking good. We all expect another class performance tonight.

If you have Messi next to you, just pass the ball to Messi.

Andy Cryer
BBC Sport in Qatar

You can't help wondering does anyone own an Argentina shirt without the number 10 on in Argentina? And are there any other shirt names than Messi or Diego?

It is absolutely incredible the sea of blue and white 10s all around the stadium.

Rio Ferdinand
Former England defender on BBC One

Australia won't be seen as a walkover, but they're certainly an easier opponent.

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC One

We started slowly, we lost to Saudi Arabia in the first game. But hopefully we see the Argentina team [that went on a long unbeaten run] before the World Cup.

According to Opta projections, Argentina have an 85.5% chance of progressing to the quarter-finals. That makes them the most overwhelming favourites of any side in the seven remaining last 16 clashes.

Australia - who the maths geniuses among you will have figured out have only been given a 14.5% chance of victory tonight - might have something to say about that, though.

Image source, Getty Images

Image source, Getty Images

Image source, Reuters

Argentina coach Lionel Scaloni has complained about his side's reduced preparation time for this game.

Australia beat Denmark on Wednesday to qualify, with Argentina defeating Poland four hours later to book their place.

"Australia, who finished second in the group, played at 6pm and we finished first but played at 10pm. We went to bed at 4am and that has an impact when you have a game in 48 hours," said Scaloni, who took over after the 2018 World Cup.

"We will break our backs on this pitch to compete, we know how difficult this World Cup is, this is football."

Just me or is four hours not really worth complaining about?

Andy Cryer
BBC Sport in Qatar

Out come the Argentines to warm-up and what a noise greets them.

A little more than 40 minutes and this place is already bouncing.

A small pocket of Australian fans are doing their best, but you can't help feeling they are going to get drowned out this evening.

Pablo Zabaleta
Ex-Man City and Argentina defender on BBC One

Very sad news to hear about Pele. He's been a true inspiration for all of us, on and off the pitch he's always been a great man.

A report in Brazil, which has not been confirmed by the BBC, says Pele is now beginning end-of-life care after not responding to chemotherapy.

Mathew Leckie took Australia into the knockout stages with the only goal in their 1-0 win over Denmark.

Premier League pair Alexis Mac Allister and Julian Alvarez netted as Argentina beat Poland 2-0 to book their place in the knockout rounds.

Andy Cryer
BBC Sport in Qatar

Image source, BBC Sport

Ahmad bin Ali awaits a humdinger of a knockout tie.

The Argentine fans are already gathering in their thousands.

It is going to be some atmosphere…