Iran: Carlos Queiroz will be without centre-half Rouzbeh Cheshmi for the rest of the tournament after he suffered a muscle injury during training. Mohammad Reza Khanzadeh is expected to replace him in the Iranian backline, with the rest of their side unlikely to see any changes from their 1-0 defeat to Morocco.
Spain: 'La Roja' could name the same side that played out a 3-3 draw with Portugal in their first game. David De Gea's performances of late have come in for criticism but Fernando Hierro confirmed on Tuesday that he will keep faith with the Manchester United man for now. Meanwhile, Diego Costa should retain his place up front after his brace in Spain's opener. Right-back Dani Carvajal has recovered from his hamstring problem and could return to the team in place of Real Madrid team-mate Nacho, despite his stunning goal against Portugal.
Iran boss Carlos Queiroz:
"For us it's a privilege and an honour to be here. It's a unique opportunity for us to play against Spain, one of the candidates to win the World Cup.
"We're in a win-win situation because it's a unique opportunity for our national team to learn more about the game and to grow as players.
"If there was a magic potion to stop the Spanish team, then $1 million would not be too much to buy it, even though we do have some financial troubles.
"We are well aware of Spain's reputation, so we'll have to play our best game ever. In the end the football gods will decide."
Spain boss Fernando Hierro on the fitness of Dani Carvajal:
"Dani is doing well. He has been training with the rest of the team for nearly one week so has recovered very well.
"He has been working with doctors, physios and the medical staff. He is available for tomorrow [Wednesday].
"I have 23 players with their own character and you can't treat them all the same.
"All I can say is De Gea will play. We trust him entirely. As we've been saying for a few years now, he's one of the two or three best goalkeepers in the world. He will play, we trust him."
Did you know?
This will be the first encounter between the two sides.
Iran have never won against European opposition at the World Cup in six attempts (W0, D1, L5).
Possible lineups:
Iran: Beiranvand; Rezaeian, Poualiganji, Khanzadeh, Hajsafi; Jahanbakhsh; Shojaei, Ebrahimi, Amiri, Ansarifard; Azmoun.
Spain: De Gea; Carvajal, Pique, Ramos, Alba; Busquets, Koke, Iniesta; Silva, Costa, Isco.