The European side struggled to break down their disciplined opponents despite dominating the overall possession throughout the competitive World Cup encounter.
The match ended in deep frustration for the tournament favorites who also had to navigate a significant portion of the contest with ten men after Nathan Ngoy's dismissal.
Experienced forward Romelu Lukaku expressed his profound annoyance at the team's inability to convert their numerous clear-cut opportunities into goals.
"We have to analyse what went wrong, because we created so many chances without scoring and that’s frustrating," Lukaku rued. "We play with too much emotion in key moments."
Iran head coach Amir Ghalehnoy praised the immense character shown by his players after securing a well-deserved result against elite opposition.
"I think it was a very exciting game," Amir Ghalehnoy said. "Both teams deserved to win; both could have taken the three points.
"I want to extend my sincere thanks to each and every player, especially Ali Beiranvand," the coach added.
Garcia admitted his squad looked uncharacteristically hesitant during their opening fixtures of the global showpiece tournament in North America.
"We lacked efficiency up front," Garcia reflected. "I expected this kind of game, with nearly 70 per cent possession, plenty of crosses and lots of shots."
"We hit the target, but we didn't test the goalkeeper enough," the manager continued.
"Playing with 10 men didn't help either."
"We’ve had matches like this before and usually scored at least three goals," Garcia concluded.
"That’s part of a slow start to a World Cup. At times, we looked a bit hesitant. We know exactly what result we’ll need against New Zealand."
Belgium must quickly rectify their attacking issues if they are to progress deep into the knockout stages of the competition.
The coaching staff faces a difficult task to restore confidence ahead of their final group fixture.