Moscow - Eight teams have already qualified for the Round of 16, leaving 8 remaining spots up for grabs.
Here's what teams in Group C and Group D need to do to keep their 2018 Soccer World Cup hopes alive.
QUIZ: Can you name all the semi-finalists in all the previous Soccer World Cups?
GROUP C
- France are through to the knockout round. A draw or win against Denmark would see them finish as group winners.
- A point against France would see Denmark qualify, as would Australia's failure to beat Peru. The Danes would top the group with victory.
- In order for Australia to qualify they must beat Peru, hope Denmark lose and also better the Danes' goal difference.
Remaining fixtures on Tuesday:
Australia v Peru - 16:00
Denmark v France - 16:00
GROUP D
- Croatia have qualified and will be group winners with a point against Iceland.
- Nigeria will qualify with a win over Argentina. A point would be enough if Iceland do not beat Croatia.
- If Argentina and Nigeria draw, Iceland will make the last 16 if they beat Croatia by a two-goal margin and also score at least one more than Nigeria.
- Argentina will qualify with victory over Nigeria coupled with Iceland failing to defeat Croatia. If Iceland do beat Croatia, then Jorge Sampaoli's side can still qualify if they beat Nigeria by two more goals than Iceland win their game. If Argentina and Iceland win and finish with identical records their fate will be decided by their disciplinary records and then the drawing of lots. Argentina have picked up three yellow cards and Iceland have none.
Remaining fixtures on Tuesday:
Nigeria v Argentina - 20:00
Iceland v Croatia - 20:00
FIFA's Soccer World Cup group ranking rules:
1. Best goal differential
2. Most goals scored
3. Points from head-to-head games between the teams involved
4. If more than two teams are tied, best goal differential from matches between the teams involved
5. Most goals scored in all matches between the teams concerned
6. Fewest points deducted based on yellow and red cards received in all group matches, as follows: a 1-point deduction for a yellow card, a 3-point deduction for a red card issued as a result of a second yellow, a 4-point deduction for a straight red, and a 5-point deduction for a straight red issued after a yellow card
7. Drawing of lots by FIFA