The disruptions to Iran's preparations for the tournament were more geo-political in nature with U.S. sanctions against the nation costing them a couple of their warm-up matches and their kit deal with Nike.
Costa was involved in plenty of battles during the match and was accused of stamping on the foot of Iran goalkeeper Alireza Beiranvand in the first half.
In the end, Iran were just unable to get the goal that would have earned them one of the surprises of the tournament, and will now need to get a result against Portugal on Monday if they are to reach the Round of 16.
Silva had Spain's best chance of the first period in the closing stages, but the attacker saw his attempt deflected wide of the post as Iran's rear-guard action saw the two teams head down the tunnel at 0-0.
Spain were looking to get the second goal with five minutes remaining that would take them top of the group, but they could not carve out another chance.
Isco was at the heart of Spain's brightest attacking moves, though it took a lucky goal to defeat Iran.
Isco was next to come close for Spain in the 52nd minute, with the Real Madrid midfielder clipping over the crossbar following smart work from Carvajal down the right.
Iran's Milad Mohammadi has left World Cup viewers in stitches after a ridiculous throw-in fail during the World Cup match against Spain.
Queiroz had no complaints about the VAR decision which ruled out Saeid Ezatolahi's strike for offside, preferring instead to rue that it had not been around at the 2010 World Cup when his Portugal were beaten by a contentious Spain goal. A draw will suffice if Iran fail to beat Portugal.
La Roja were their usual composed selves in possession but were frustrated by Carlos Queiroz's well-organised defence through the opening 45 minutes, with over 80 percent of possession bringing just one shot on target.
Bilic argued that he had sympathy for Spain due to how Iran had set up defensively but former England striker Ian Wright and Keane seemed to disagree strongly with the former Hammers boss with Wright highlighting that Spain should have played better in the first-half while Keane threw his eyes to the heavens.
For Iran to finally achieve their dream against Portugal, Queiroz thought, would be all the more remarkable given the gulf that has opened up between European countries and the rest of the football world.