This would be a very interesting way to decide group winners..
Carlos Queiroz will send his Iran team out to display the "three Rs" of respect, realism and romanticism when they take on Portugal on Monday.
Bottom side South Korea could also still go through, but they need to beat Germany by several goals and hope for a Mexico win against Sweden.
They have finished top of their group in three of the last four World Cups, with the only exception their early exit in 2014. Whichever team wins by more, wins the group. Can advance with a draw if Croatia beats or draws Iceland.
Midfielder Koke will hope for a recall after being dropped in favour of Lucas Vazquez for the win over Iran.
Brazil would be safely through with a win or a draw against Serbia and will top the group unless Switzerland better their result, or match it with a better goal margin. Spain will definitely qualify if they defeat Morocco, with top spot depending on the other result.
Spain and Portugal are also level on goal difference and goals scored and, since they drew, if their final results are the same the group could be decided by fair play points. Wins for Iceland and Argentina means tiebreakers.
Serbia were unlucky to not get at least a point against Switzerland, so could provide a massive shock against Brazil, although it seems unlikely.
All sorts of outcomes are possible here with Croatia, on six points, through but the other three teams still in the hunt.
Australia need to beat Peru, also at 2am, and hope Denmark lose. They can also move on with a loss to the Swedes if Germany lose to or draw with South Korea, who have no points.
However, complicated three-way ties are possible, for either places 1-3 (if Sweden beats Mexico AND Germany beats South Korea) or places 2-4, (if Mexico beats Sweden AND South Korea beats Germany).
Germany will go through with any win should Sweden fail to beat Mexico.
England and Belgium are guaranteed to progress but their finishing positions will be decided by their meeting on Thursday. England are now on two yellows to the three of Belgium. I soon felt certain that they are a very strong team: nine wins, one draw, conceding only two goals with Syria when they qualified.
This is a fairly straightforward group, with the two qualified teams and the two eliminated teams playing each other.
Japan need only draw with Poland, who have been eliminated, to progress to the next round. Poland have been eliminated.