Iranians had hoped for a repeat of their 1998 World Cup victory over the United States, but Tuesday's 1-0 loss in Qatar sent Tehran into stunned silence as they were eliminated from the competition.
There was no repeat of last Friday's street celebrations when people danced after Iran defeated Wales.
A dozen families had gathered in a cultural center in the north of the capital at the start of the evening to watch the game in Qatar on a large screen.
Parents and children shouted, "Come on, come on!" while waving Iranian flags.
A US goal in the 38th minute quickly dashed Iran's hopes of repeating its 1998 victory.
Due to decades of animosity between the geopolitical adversaries, the event was dubbed the "Mother of all football matches" in the lead-up.
Asghar Mohammadi, a 50-year-old shopkeeper, was startled by the pleasant environment on the pitch as he watched the game.
"Many predicted that this game would be tainted by politics, yet we witnessed just cordial interaction amongst the players on the field." "Whenever a player fell, his opponent lifted him up," he explained.
He said, "Our guys fought with all their might, particularly in the second half."
The match generated headlines despite not being the World Cup final because of its symbolic and political significance to two countries that have not maintained diplomatic relations for more than four decades.
Amir Moradian, a 45-year-old topographer, stated, "Politicians occasionally exploit soccer as a political instrument, but sport should not be politicized."
"I wished for Iran to win the game. I was devastated by the outcome. This setback makes people upset, which is natural, but we must not lose hope and focus on future competitions," he stated.
According to social media videos, demonstrators in Iranian Kurdistan let off fireworks and cheered following Iran's loss on Tuesday.
The Islamic Republic has mobilized state security forces against what it terms "riots" that erupted following the death of Mahsa Amini, a 22-year-old Kurdish woman, on September 16, three days after her arrest for allegedly violating Iran's dress code for women.
Her hometown of Saqez, along with other cities in the western province of Kurdistan, had been the epicenter of anti-clerical rule rallies.
"Citizens of Saqez have begun to rejoice and let off fireworks following America's first goal against Iran's football team," tweeted the London-based Iran Wire website.
It distributed a video of pyrotechnics with cheering in the background. AFP was unable to quickly confirm the substance.
Another video by Kurdish activist Kaveh Ghoreishi shows a nighttime neighborhood in Sanandaj city with cheering and screaming horns after the United States scored the game's lone goal.
According to YouTube recordings, Mahabad, another city in Kurdistan, also utilized fireworks following Iran's loss.
According to the Norwegian human rights organization Hengaw, Iranian cars in Mahabad honked their horns to celebrate the United States win.
It was reported that fireworks were also seen in Marivan, another city in the Kurdistan region where security forces had conducted a violent crackdown on the rallies.
In addition, fireworks and applause were heard in Paveh and Sarpol-e Zahab, Kermanshah province.
Following the protests, the Iranian national team was subjected to government and widespread criticism, with some Iranians even supporting the other teams.
After the loss, Saeed Zafarany, an Iranian sports writer, tweeted, "Who would've thought I'd jump three meters to applaud America's goal?"
Elahe Khosravi, a podcaster, also tweeted: "This is the result of playing the middle. They were defeated by the people, their adversary, and "even" the government.
"They were defeated. Both on and off the field," tweeted journalist Amir Ebtehaj from Iran.
The US victory eliminated Iran from the World Cup and guaranteed the Islamic republic's archrival a spot in the Qatari elimination round.
Former journalist Hamid Jafari tweeted, "And the Islamic republic football team circus is gone."
"Now the news of tyranny cannot be concealed behind the victory or defeat of the favorite team of the security forces," he said, referencing to videos of the Iranian police celebrating the team's earlier victory against Wales while deployed on the streets.
At least 448 individuals, according to the Oslo-based organization Iran Human Rights, have been killed by Iran's security forces during the crackdown on more than two months of protests.