Despite the frustration of conceding an 88th-minute equaliser to Ronaldo following two goals from Diego Costa and a stunning strike from Nacho, Isco believes Spain's resolve remains intact.
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. "I hadn't expected that the match against Iran would be so hard".
Spain took a big step towards reaching the knockout stages with their hard-fought win over Iran on Wednesday.
Spain and Portugal are tied for second in Group B with one point each, while Iran lead the group with three points after beating Morocco 1-0 earlier Friday, thanks to an own goal from Aziz Bouhaddouz. Do not cut, copy or lift any content from this website without our consent.
The defeat leaves Iran on three points, following their last-gasp win over Morocco. Iniesta found Diego Costa in the box, and Costa's shot hit Ramin Rezaeian, before rebounding back off the Atletico Madrid striker and into the net.
Antoine Griezmann was the first footballer in World Cup history to have successfully scored a goal after a VAR review in the match between France and Australia.
Iran football team
Few will be giving the Iranians any chance when they take to the field at the Kazan Arena but, firstly, that could play in their hands as they would effectively be able to play sans pressure, with the weight of expectations firmly on Spain's shoulders.
Facing a very compact Iranian team that came out to defend, Spain pressed high and controlled much of the game but found it hard to threaten against Iran's 10-man defense. David de Gea, who had a poor perforance against Portugal, is expected to start in goal.
Iran fans all but tore their hair out late on when Vahid Amiri brilliantly nutmegged a defender to send a cross into Mehdi Taremi, but the forward sent a very gettable header from six yards out sailing over.
Meanwhile FIFA hss fined the Mexican Football Association 10,000 Swiss francs ($10,000) for homophobic chants heard during their World Cup fixture against Germany.
Lucas Vazquez was the surprise name in Fernando Hierro's XI, one of two changes on the night, the other being Dani Carvajal at full-back to form a new-look right side.
An Iran win against a tough Portugal squad on Monday will punch the Persian team's ticket to the final 16.
Diego Costa was the match victor for Fernando Hierro's side in the encounter after they were held to an enthralling 3-3 draw last Friday by Portugal. "We're a team and we have to stick together".More news: Colombia resumes training after surprise loss to Japan