Iran and Spain could not be separated at half-time, with David Silva enjoying perhaps the best chance of a goalless first half when his acrobatic attempt to score was closed down by the Team Melli defence. The kickoff of the second half, however, saw the Spanish side pick of momentum in their chase for a goal, creating a couple of chances.
The forward scored when Ramin Rezaeian's attempted clearance bounced off the Spaniard's leg and into the net in the 54th minute.
Saeid Ezatolahi nearly leveled the score for Iran in the 62nd minute, but the Iranians' cheers were cut short when the goal was ruled offside with the help of video assistant referee (VAR) system.
Dani Carvajal told AS after the game that while he has no problem with defending deeply and committing fouls, "Iran's time-wasting, pretending to be injured or hurt - to me, that's not football, it's disloyal".
Spain and Portugal shared the spoil in another's group match.
With this victory in the basket, both Spain and Portugal have four points in Group B following their 3-3 draw and subsequent 1-0 victories. Do not cut, copy or lift any content from this website without our consent.
"In this moment we are more concerned because one member of our staff in difficulty from health point of view after VAR decision", Queiroz said.
Hierro has been hired to lead Spain at the World Cup as a replacement for Julen Lopetegui, who was sacked two days before the national team's opening match in Russian Federation.
"The team sits back and that is a tactical strategy that is part of the game", Carvajal said.
Iran will be without defender Roozbeh Cheshmi, who will miss the remainder of the World Cup after picking up an injury during training.
After parking the bus for so long, the Iranian team searched for an equalizer.
After Wednesday, Team Melli will finish their group stage campaign on June 25 against Portugal, which will pose a different but equally hard obstacle.
That goal is one step closer thanks to Costa's intervention, but Spain need to add more strings to their bow and be more malleable in the face of their opponent after being slow to adapt against Iran. At the same time, Iran will take on Portugal, knowing that a win over Cristiano Ronaldo's side will be enough for them to reach the round of 16.