Sami Khedira and Mesut Ozil returned to the starting line-up but Thomas Mueller was left out as Germany look to avoid an embarrassing World Cup exit at the hands of South Korea in their Group F decider on Wednesday.
Son netted two goals in the tournament, including the second goal against Germany.
Iceland started well in their first World Cup - Hannes Halldorsson saved a Messi penalty to earn a point - but couldn't keep the momentum going. This tournament, like so many before it, has once again proven that the World Cup is anything but predictable.
Reigning world champions Germany were dumped out during the group stages after a horror showing in Russian Federation.
With 16 teams remaining, the tournament now moves to an elimination bracket, pitting teams against one another in decisive matches - the dramatic draws of the group stage will now give way to exhilarating extra time and the overwhelming anxiety of penalty shootouts.
Top stat: The 307 passes successfully completed by Spain captain Sergio Ramos is more than any other player at the World Cup.
The powerful Mannschaft, the dominant force of world football recent years, crashed out miserably in the first round of the World Cup, and nobody saw it coming. Modric has scored in two games out of three at Russian Federation 2018, while Eriksen's shoulders carry both Denmark's creative and goalscoring threat.
Pele's great Brazil side rocked up in England having won the previous two World Cups. Sweden topped the group, and Italy went home. The Samurai Blue, Asia's last team at the finals, will be outsiders having never reached a World Cup quarter-final, while only Russian Federation have a lower Fifa ranking.
Sweden's Ludwig Augustinsson put his side ahead against Mexico and in return, he sank Germany's hopes of progressing.
Out of shape after the long journey by sea, the Italians played just two matches, losing 3-2 to Sweden before beating Paraguay 2-0.
They did just that by overcoming Senegal 1-0, and the coupling of that result with Poland's 1-0 triumph over Japan meant Aliou Cisse's side were eliminated on fair play rules.