Mexico v USA | Second round
Jeonju | Mon 17 June | 07.30 BST
BBC One/Radio Five Live
Well over half a million US citizens are living in Mexico and Monday's second-round meeting is going to divide many bi-national families.
US Embassy statistics identify approximately 600,000 of their citizens in Mexico, more than anywhere else in the world outside the United States.
Many have put down permanent roots south of the border and their children were born here, increasing the loyalty split.
Diane Hamelberg de Hernandez has lived in Mexico for 28 years. Her husband is Mexican and their 20-year-old son Alfredo has dual nationality.
"Oh, there will be havoc in my house," she told BBC Sport Online. "I want the USA to win, much as I love Mexico.
"But I'm not even going to watch it. I'll go to another bedroom. I'll hear about it, believe me. They'll wake me and tell me what the result is."
So, what if Mexico win?
"I'll be very gracious," she said. "I live here and adore Mexico. But, in my heart, I would like to see the USA win."
And if the USA prevail?
"Wow. I don't know if I can go to work. I agree it's only a game, but the further teams progress, the more the frenzy increases."
Meanwhile, Mexico president Vicente Fox has been following the national team's fortunes closely.
He watches games wearing the number 13 shirt given him by the players at a reception in the presidential palace before their departure.
After the draw against Italy, President Fox sent a message to the team.
"The whole country is overflowing with happiness and we are truly proud," he said.