With France already through from Group D, this has essentially become a winner-takes-all encounter.
Australia have the upper hand going into this fixture, following their win over Tunisia in Saturday's early offering, moving them into second with four points.
That was just Australia's third-ever World Cup win, and their first since 2010 when they beat Serbia in South Africa.
Despite that win in 2010 though, that was not enough to take them through even after collecting four points, and that exact fate will repeat itself if they fall to defeat here.
Their form in previous World Cups against European sides presents cause for concern though, as they have lost eight of their 11 meetings with sides from the continent, but they did manage a 1-1 draw with their upcoming opponents in the last iteration in Russia four years ago.
Like 2010 though, they also failed to make it through the groups, as in five finals appearances, they have made the knockout round just once, in 2006.
At these finals, they have been strong starters, and that could serve them well in a tense, potentially close-fought game here.
Australia took the lead against both France and Tunisia inside the opening quarter of the game, and in the latter, it was the first time they have ever led at half-time in a World Cup match.
A first clean sheet at the tournament since 1974 was most welcome too, and if they can repeat that feat here, it will see them progress at Denmark's expense.
It would be an incredible achievement for the Socceroos to go through considering they needed to win two sets of playoffs to make it to Qatar, after winning just one of their final seven AFC qualifiers.
In contrast, Denmark were imperious in qualification, winning their opening nine qualifiers with eight clean sheets, but now face the very real prospect of early elimination.
No side picked up more points in UEFA qualification than Kasper Hjulmand's side, but a repeat of their result against the Aussies in 2018 will send them home.
They can take inspiration from the fact that they lost both their opening two games of Euro 2020 and still managed to make the semi-finals thanks to a phenomenal display against Russia in their final group game.
Previous form at the World Cup also gives cause for optimism, because unlike Australia, they have made it out of the group stage in four of their five finals appearances.
They must end a five game winless run at the World Cup to do so though, as the defeat to France last time out ended a run of four successive draws.
Facing Les Bleus on the biggest stage was just too much for the Danes, as they fell to a deserved defeat despite beating Didier Deschamps' side twice in the UEFA Nations League this year.
Nathaniel Atkinson missed Australia's win over Tunisia after picking up a knock to his ankle against France in the group opener.
Brescia's Fran Karacic came in to replace Atkinson at right-back, the only change for that game, and given the fact they won, it is unlikely that manager Graham Arnold will change anything, injury-permitting.
Martin Boyle remains a big miss though, as the Hibernian forward suffered an ACL injury on the eve of the tournament and will miss the rest of the season.
Thomas Delaney will miss the rest of the tournament for Denmark after suffering a knee injury in the first half against Tunisia on matchday one.
This saw Mikkel Damsgaard come into the side as Hjulmand changed shape from 3-5-2 to 3-4-3, taking a man out of midfield and using the Brentford man out wide.
Jesper Lindstrom and Victor Nelsson were both brought into the side against France to replace Andreas Skov Olsen and the ageing Simon Kjaer, whose game time is being managed sensibly, but both are likely to come back in.
Australia possible starting lineup:
Ryan; Karacic, Souttar, Rowles, Behich; Leckie, Irvine, Mooy, McGree, Goodwin; Duke
Denmark possible starting lineup:
Schmeichel; Andersen, Kjaer, Christensen; Kristensen, Hojbjerg, Eriksen, Maehle; Skov Olsen, Dolberg, Damsgaard
We say: Australia 0-2 Denmark
Even though they only need a draw to progress, Australia will find it difficult against a determined Danish side who will be desperate not to be one of the major underperformers at these finals.
Denmark performed when the pressure was on against Russia at Euro 2020, and they could well pull out a similar display here.
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