World Cup permutations: How can Argentina qualify for last 16?
Argentina are the biggest World Cup name in danger of being sent home early from Russia 2018.
After taking a single point from their first two matches in Group D, Lionel Messi and his side need to produce something special against Nigeria to stay in the tournament.
But there are plenty of other teams yet to secure their place in the knockout stage of the World Cup, while a few nations are already assured of their exits.
Here, we wrap up everything you need to know about the permutations for all eight groups heading into the final round of fixtures.
Russia and Uruguay have already confirmed they will be in the last 16, but top spot is still up for grabs when they meet in Samara on Monday. But with Spain potentially finishing behind Portugal in Group B, the advantage may be minimal.
In the other game between Mohamed Salah's Egypt and Saudi Arabia, only pride is at stake. Saudi Arabia have finished bottom of their group at their past three World Cups.
Euro 2016 champions Portugal and Iberian neighbours Spain were strongly tipped to be the two sides to go through from Group B and with one game remaining, that situation looks set to happen.
Spain play already-eliminated Morocco in their last game and they only need a point, while Iran have to upset Cristiano Ronaldo's Portugal to leapfrog them in the table and qualify.
Despite failing to impress in one-goal wins over Australia and Peru, hotly tipped France are guaranteed of a place in the round of 16. Les Bleus play Denmark in their final fixture, with the latter requiring a point to be certain of following them through Group C.
With Peru out after failing to score in either of their defeats, Australia will be hoping for three points that would draw them level with Denmark, should they lose to France.
If teams finish level on points, goal difference will be used to decide the final group placings. Goals scored is the next criteria, followed by the head-to-head record of the tied teams. Should there still be no winner, fair play points will be tallied. And if it is still a tie, FIFA will draw lots.
Argentina's fate is out of their hands, but Nigeria's defeat of Iceland on matchday two was a good result for the two-time winners. Messi's men have to beat the Super Eagles to move onto four points, giving themselves a chance of progressing.
But they could be out anyway if Iceland can beat Group D leaders Croatia, who may feel their last match is a chance to rest players for the knockout rounds. Nigeria captain John Obi Mikel has already warned Croatia to play their strongest side against Iceland.
Should Argentina be knocked out, it will be the first time they fail to make it through the group stage in 16 years.
While Argentina have toiled in Group D, South American rivals Brazil look set to make it through Group E - even though their passage has not been straightforward with two late goals needed to down Costa Rica in their last match.
Tite's men are through if they get at least a point against Serbia in Moscow on Wednesday. After Xherdan Shaqiri's late winner in Switzerland's 2-1 defeat of Serbia, they are in pole position to follow Neymar's side through.
Costa Rica are out, with Switzerland only needing to avoid defeat to guarantee qualification from the group stage for the third time in the last four World Cups.
Toni Kroos' dramatic late winner on Saturday kicked Germany's campaign into gear and they can secure their progression to the last 16 if they match Sweden's result in the final game.
Mexico only need a draw against Sweden to qualify, while the latter will go through should they better Germany's result against South Korea.
South Korea face an uphill challenge, they have to beat the defending world champions and hope Sweden lose, while also improving their goal difference.
Things are very simple for England and Belgium, they are both already through and should there be a winner in Kaliningrad on Thursday, they will top the group.
Were the clash to end as a draw, first place would be decided on the number of cards received due to identical records elsewhere. England currently have one fewer.
Should both sides finish with the same number, lots will be drawn.
Poland are out, but the remaining three teams could still reach the knockout stage.
Draws for Japan (against Poland) and Senegal (against Colombia) will send the top two through, however, Colombia will qualify if they beat their African rivals.
If Colombia win, Japan will need to lose by fewer goals than Senegal to progress.