Saul and Marco Asensio scored before goalkeeper Lovre Kalinic put one in his own net, and the rout was completed in the second half thanks to goals from Rodrigo, Sergio Ramos and Isco - all three assisted by Asensio.

The result in Elche leaves Spain top of Group A4 with six points after they opened their campaign with an away win against England on Saturday.

Croatia, who drew 1-1 with Portugal in a friendly on Thursday, suffered the heaviest defeat in their history, with their previous worst result being the 5-1 loss to England at Wembley in 2009.

They were missing the likes of goalkeeper Danijel Subasic and forward Mario Mandzukic, who retired from international football after the World Cup, and injured Liverpool defender Dejan Lovren.

Croatia did have World Cup Golden Ball winner Luka Modric, Barcelona midfielder Ivan Rakitic and Inter Milan winger Ivan Perisic in their line-up but that could not prevent a heavy defeat.

They lost right-back Sime Vrsaljko to injury after 20 minutes and fell behind three minutes later.

A flowing team move from the hosts ended with Dani Carvajal crossing from the right for Saul to head in from close range.

Two goals in quick succession then put Spain firmly in charge as Real Madrid forward Asensio took centre stage.

First he took control of a loose pass in the 33rd minute and found the top right corner from 25 yards.

And two minutes later Asensio thumped an effort off the crossbar which rebounded off goalkeeper Kalinic and into the net

Rodrigo scored the fourth four minutes into the second half, running on to a through ball from Asensio and slotting through the legs of Kalinic.

Captain Ramos headed in unmarked from an Asensio corner in the 57th minute and the scoring was completed with 20 minutes left as Asensio again combined with a Real Madrid team-mate, this time teeing up Isco to strike in from near the edge of the penalty area.