A revamped but businesslike Croatia topped their World Cup group as Ivan Perisic's 90th-minute goal helped them maintain their perfect record with a 2-1 win on Tuesday that also ended Iceland's qualification hopes.
Perisic, with Luka Modric the only player not rested, struck in the last minute to set up a round-of-16 game against Denmark after Milan Badelj's second-half goal was cancelled out by Gylfi Sigurdsson's penalty.
Iceland, who had a handful of good chances, were tipped to surprise at the World Cup after their finish at Euro 2016 but finish last in the group with one point.
Argentina took second place and will face France after a 2-1 win against Nigeria.
With qualification assured, coach Zlatko Dalic fielded the youngest Croatia team at a World Cup, making nine changes from the team that beat Argentina on Thursday.
As expected, Croatia controlled midfield and Iceland were perfectly happy with the scenario, looking to hit their opponents on the break.
Croatia's possession was sterile but, with a draw enough to top the group, they had little incentive.
Five minutes before the break, Alfred Finnbogason played a one-two with Sigurdsson, but his shot from just inside the box went wide.
On the stroke of halftime, Aron Gunnarsson fired an angled shot that was bound for the top corner until Lovre Kalinic tipped it away.
Croatia had their first clear chance when Badelj's missile crashed onto the bar six minutes into the second half. The midfielder was more accurate two minutes later as he thundered a volley into the back of the net to open the scoring.
Iceland reacted swiftly. Sverrir Ingason forced Kalinic into another spectacular save seconds before his header shaved the top of the bar.
They were rewarded in the 76th minute when second-half substitute Dejan Lovren handled the ball and Sigurdsson rifled the resulting penalty into the roof of the net.
Iceland's hopes were up again, but Perisic's finish after he slipped into the left side of the area made sure his side finished the group stage with three wins in three games.