Follow live updates from Group B as Spain takes on Iran.
Spain began the World Cup in disarray after the federation fired coach Julen Lopetegui just 48 hours before its opening match against Portugal. It didn't seem to rattle the team, though, as Spain outplayed Portugal but ended in a 3-3 draw because of Ronaldo's hat trick.
Diego Costa scored twice for Spain to emerge as an early star of the World Cup, but goalkeeper David De Gea had a rough opener. He let a shot from Ronaldo slip through his fingers in a mediocre performance, but the team said he will start against Iran.
"De Gea is feeling fine. Obviously he knows he made a mistake," Spain defender Nacho Fernandez said. "The most important thing is that the team protects him, supports him to death."
Iran goes into the match at Kazan Arena leading Group B after its victory over Morocco and hopes its stingy defense keeps the team on track to advance to the next round.
Iran arrived in Russia with the second best qualifying record in the world in the final stage of Asian play with nine victories in 10 games. Iran gave up only three goals, two in the last match after it had already qualified for the World Cup.
The win 1-0 win over Morocco was a highlight for the national team and takes pressure off the team's chances of advancing.