France will play the runners-up from Group C, while Australia will face the winners.
Tunisia has managed to hold on to a shock victory over France after a goal was ruled out by VAR in the final minute of stoppage time.
Substitute Antoine Griezmann had volleyed in a dramatic equaliser at the Education City Stadium.
The decision meant Tunisia's captain's brilliant first-half goal proved to be the winner.
Despite the defeat, defending champion France still won its World Cup group.
Australia also made it through -- for the first time since 2006, beating favoured Denmark.
For Denmark, the match was a major disappointment. The team hoped that Tunisia would not beat France to advance to the round of 16.