Iran were thrashed 6-2 by England but recovered to beat Wales 2-0.
The USA have two draws: 1-1 with Wales and 0-0 against England.
Iran have never gone past the group stage.
USA returns to World Cup for the first time in eight years.
Excitement is high amongst US fans
Watch parties in Los Angeles
At a watch party in downtown Los Angeles, fans spill out of a bar and into the street to watch as the US prepares to square off against Iran.
A majority of fans are cheering on the US, but a contingent of Iran fans are hoping for a historic win that could catapult the team into the second round for the first time in history. Protests in Iran challenging the government have deepened political divides among the large Iranian diaspora community in Los Angeles, and have left some feeling conflicted about rooting for the national team.
Some US fans are also showing their support for the protests.
“The fact that Iranian players have been arrested and there have been threats to players and their families on the national team is scary,” said Andrea Fluker, who is cheering for the US team with her husband. “I wanted to support my country while also showing support for the women of Iran.”
Politics around World Cup “very annoying”
Justin Brown from Texas says he wished there was “one thing in the world that was not politicised”. His mother Carol said she found the political discourse around the World Cup “very annoying”, adding that the occasion was a time “where people can come together and get to know one another”.
“It’s easy to lob insults from thousands of miles away but when you come to an event like this … you realise we are all humans,” she added, showing Al Jazeera a smiling image of her and an Iranian fan at the game.
Justin added that he does not agree with calls to remove teams from the World Cup due to politics and that all countries, including his own, did not “have a clean record” when it came to human rights.
The lineups are in
Iran: Beiranvand, Rezaeian, Majid Hosseini, Pouraliganji, Mohammadi, Noorollahi, Ezatolahi, Hajsafi, Gholizadeh, Azmoun, Taremi
USA: Turner, Dest, Carter-Vickers, Ream, Robinson, McKennie, Adams, Musah, Weah, Sargent, Pulisic
Despite all the politics surrounding the game, Iranian fans who Al Jazeera spoke to were largely hesitant to speak about the political and social tensions back home.
People that Al Jazeera approached either shrugged or stated “no politics questions” when asked about the anti-government protests in Iran.
The protests were triggered by the death in police custody of Mahsa Amini, 22, in September. She had been detained by the so-called morality police for allegedly not following the country’s dress code for women.
When asked if the team and supporteres at the World Cup should continue to show solidarity with demonstrators back home, Golnaz, from Tehran, said: “The Iranian team should be the global voice of the country.”
She declined to be photographed or give her last name, as she hurried along with her friend to another part of the stadium.
But what about the football?
Barring what would be a surprise victory for Wales against England, the USA has to win to go through to the World Cup’s knockout stages, while the Iranians only need a draw.
That puts Iran’s manager Queiroz in a bind. Play to his own defensive instincts, and go for the draw, while betting on the English avoiding a loss? Or play to Iran’s attacking strengths, with star strikers Sardar Azmoun and Mehdi Taremi up top?
Where do Iranian fans stand?
Iranian fans, for their part, are still divided over whether to even support the team, in light of the protests calling for women’s rights in Iran.
Some in the anti-government camp fear that an Iranian victory over the USA will be used by the government for propaganda.
Iran coach Carlos Queiroz brushed off suggestions that the flag furore would be used to motivate his players.
“If, after 42 years in this game as a coach, I still believe I can win games with those mental games, I think I’ve learned nothing about the game,” Queiroz said.
It’s just a game
Coach Gregg Berhalter said on Monday his players and team staff had been in the dark about the flag gesture and sought to de-escalate tensions by emphasising that politics would not be a factor on Tuesday.
“When I think about this match, I know that a lot of other constituents have a lot of other feelings towards it,” Berhalter said.
“But for us, it’s a soccer game against a good team and it’s not much more than that. It’s a knockout game between two good teams that want to get to the next round.”
And the controversies in the World Cup?
Since the World Cup began, there have been controversies.
Iran has asked for the USA to be thrown out of the tournament after a US Soccer Federation social media post used an altered version of the Iranian flag.
And the former USA manager, German Jurgen Klinsmann, has angered Iran by saying that unsportsmanlike behaviour was part of Iran’s “culture”, while speaking to the BBC.
What are their non-sport issues?
Their political problems go back decades, but recently, Iran and the US haven’t been able to reach agreement on reviving the Iran nuclear deal. Washington unilaterally backed out of the pact in 2018 and reimposed sanctions on Tehran.
Ongoing anti-government protests in Iran have attracted the world’s attention and the condemnation of the US government. The Iranians accuse the Americans of being among those behind the protests.
One highlighted match
Since the draw for the World Cup was made in April, the Group B game between the US and Iran has stood out as one of the highlights of the group stage of the tournament in Qatar.
Even if little had been riding on the result, the game at Al Thumama Stadium would have been loaded with political overtones. It is only the third meeting on a football field of two nations who share more than 40 years of ideological enmity.
Two countries divided by politics and history
Iran and the USA, two countries divided by politics and a history of enmity, are being brought together by the World Cup.
That was how the game was billed at the 1998 tournament in France, where Iran won 2-1.
Fast forward to 2022, and the two have been drawn together again. The political divide is still there – and if anything, it’s more entrenched.
Good evening from Doha.
It’s 6pm here (15:00 GMT), and we are preparing to witness a historic game: Iran vs Team USA at 10pm (19:00 GMT) at Lusail Stadium.
Follow all the latest news and updates leading up to the game and then during the match right here.