Spain-Russia. This is where the party ends for the hosts. Spain haven't always been at their best so far, but Russia's 3-0 loss to Uruguay is probably more telling than anything else. The Russians beat up on lesser opponents, and deserve props for that, since they were supposed to be one of those lesser opponents. But they aren't going to beat Spain. I wouldn't be surprised if they are held scoreless once again. I expect Isco for Spain and Aleksandr Golovin for Russia being their team's best players.
Here are highlights from a match between the two at the 2008 Euros. Ten years ago, but some familiar faces for 2018 World Cup fans, although the faces are older and the hairstyles have changed:
Croatia-Denmark. Croatia should roll on, having won all three of their group matches. Ivan Rakitic was dominant against Argentina, and he might find good pickings here, as well. Denmark's hopes lie in keeper Kasper Schmeichel, who is having a great tournament. Denmark only allowed one goal in three games, and that came via a penalty. On the other hand, Denmark has only scored twice so far. I think they will struggle to score in this one.
These teams haven't played a non-friendly match since 1997, so here's a different kind of highlight: Croatia-Denmark 2018, played on FIFA 18. Fun for a bit, but spoiler alert: no one scores until around 21:50 of the video.