The United States and Iran meet in a politically charged winner-takes-all World Cup clash on Tuesday as England aim to reach the last 16 as group winners with victory over Wales.
Ever since the draw for the tournament was made in April, the Group B game between the US and Iran has stood out as one of the highlights of the first phase in Qatar.
Even with little riding on the result, the game at the Al Thumama Stadium would have been loaded with political overtones, only the third meeting on a football field of two nations who share more than 40 years of ideological enmity.
But Tuesday's match carries an additional dimension with both teams knowing that a win will see one of them advance to the knockout rounds while the loser is eliminated.
As if that wasn't enough, simmering tensions flared up at the weekend after the US Soccer federation posted a modified version of the Iranian flag on their social media feeds.
The move infuriated Iranian football chiefs, who lodged a complaint with world governing body FIFA demanding sanctions.
US Soccer initially said the altered flag was intended as a gesture to show support for women protesters in Iran, before subsequently deleting the various posts.
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."
Iran counterpart 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," the Portuguese coach said.
In Tuesday's other Group B game England will be looking for a win over Wales as they bid to qualify for the last 16 as group winners.