In the more likely situation that Spain secure victory, they will enter their final group encounter in a much more comfortable position for reaching the first knockout rounds. Portugal and Iran are also yet to play each other.
But he was ruled off-side by the VAR, prompting howls of derision from white-clad Iranian fans.
The result put Spain joint top of Group B with Iberian rivals Portugal on four points ahead of their last match against the already eliminated Morocco.
Iran's defensive setup was hardly a surprise but Hierro's side appeared to have no set idea of how they were going to get through.
6 - Hierro's big selection decision was to start Real Madrid winger Lucas Vazquez, and it did not work.
In order to avoid any kind of drubbing Iranian coach Carlos Queiroz adopted a safety first approach.
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Tessa Thompson also returns as Adonis' love interest, Bianca, and Coogler is on board as an executive producer. Caple Jr. added: "It's an honor to be a part of the franchise and work with such a thoughtful team".
"I was very calm because there are a lot of cameras and I had the reassurance of knowing I had not done anything", he explained to reporters after the final whistle.
It was not until the 25th minute that Spain had a shot on target, with Silva sending a free kick straight into the arms of keeper Ali Beiranvand. Not having the impact on general play he would have hoped for.
Latching onto an incisive pass from Andres Iniesta, Diego Costa did well to turn his man but the covering Ramin Rezaeian was poised to snuff out the threat. But instead of releasing the ball, Mohammadi stopped his movement. But his unique ability to unsettle a defence led to the ball ricocheting to net off his knee for the only goal, which counted as his third of the tournament.
The rest of the Spanish players look for the No.22 when they have the ball and Isco is nearly always there, ready to receive it and pass it on.
A scrappy second-half goal by Diego Costa broke a Persian stonewall and lifted Spain to a 1-0 win over a courageous Iran in a nerve-jangling World Cup clash on Wednesday.
FW Marco Asensio, NR - Didn't really feature late on.