Here is a look at what Portugal, Iceland, Austria and Hungary need to do in their final group game to progress into the last 16.
Iceland (2 points) vs Austria (1)
Victory for Iceland will see them finish as group winners, if Hungary loses to Portugal and Iceland score the same number of goals as Portugal. Both Iceland and Portugal have two points but Iceland are ahead on goals scored (two versus one).
If Hungary beat Portugal, then a Iceland win will see them finish second with a win or draw. If Hungary draw then Iceland need to overturn the goal difference on Hungary (Hungary are currently +2 and Iceland are 0).
A draw means Iceland finish on three points and possibly third, which could be enough to make the next round.
If Austria win, that will be good enough for second as long as Portugal do not beat Hungary. A Portuguese win will mean Austria can finish no better than third but four points is likely to see them qualify as one of four best third-placed teams.
Hungary (4) vs Portugal (2)
Hungary can top the group with a win. A draw would also do the trick as long as Iceland fail to beat Austria.
Hungary will finish second if they lose against Portugal and Iceland fail to win, and will finish third if they lose and Iceland win.
They are guaranteed of finishing third and with four points, will fancy their chances of qualifying for the knockout stage.
Cristiano Ronaldo and Co. know a win will guarantee them progression into the last 16. They could finish as group winners if Iceland do not win.
A draw will see them finish on three points and possibly third, which could be enough to make the next round. If they lose, they will be eliminated.