The USA and Mexico are neighbours who have been sorting out their differences since the days of The Alamo.
In the Concacaf qualifying campaign, both sides chalked up home victories en route to Japan and Korea.
Now they are battling for a place in the last eight.
BBC Sport Online looks at the match-ups that could decide the game.
Torrado has emerged during the competition as a key and influential player in the Mexican midfield.
Before the tournament Torrado was not a regular starter under coach Javier Aguirre, who had doubts over his discipline.
But the 23-year-old has been able to combine his combative edge with his undoubted skills to provide Mexico with a cutting edge.
Like Torrado, Reyna is one of the few players in his team plying his trade in Europe.
Reyna is considered the USA's best outfield player, rated highly enough for Sunderland to pay £4.5m for him.
His vision and range of passing marks him out as the USA's playmaker, and if given the space and scope, can provide the ammunition for pacy front men such as Clint Mathis.
Reyna may find that space hard to come by, though, as he will find Torrado policing him closely from the first whistle.
Tony Sanneh v Cuauhtemoc Blanco
Sanneh is tall, pacy and athletic, showing an ability to work the right flank and provide useful support.
But there are times when he looks what he is - a midfielder converted into a defender.
His alarming tendency to switch off and lose his marker could prove costly for the USA, as the wily Blanco is just the man to exploit any lapses of concentration.
Blanco is more than just the player who patented the 'Bunny Hop' move where he leaps over challenges with the ball trapped between his heels.
The 29-year-old has been Mexico's inspiration and can be at his most dangerous when dropping deep.
Going into areas where central defenders are not keen to follow his eye for a pass enables him to create chances for others, just as he he did in setting up Jared Borgetti for Mexico's goal against Italy.
Sanneh will have his hands full in trying to keep the lid on Blanco's skills, while the Mexican will be looking to exploit the space behind the Nuremburg defender when he surges forward.
Brad Friedel v Jared Borgetti
Friedel had to fight off Kasey Keller for the USA number one keeper's spot before the tournament, and the Americans are probably glad he did.
The giant Blackburn stopper has been inspirational for the USA, saving two penalties in their run to the last 16.
At times, Friedel has been a one-man barrier to the opposition behind a creaky American defence, and even he was powerless to deny Poland three goals in the USA's last group match.
Borgetti emerged with six goals during Mexico's qualifying campaign.
A tall, rangy striker, he is good in the air and will be competing with Friedel for the crosses that the Mexican wide players are sure to provide.
Friedel's giant frame makes him a big psychological barrier to any striker and Borgetti will have to make the most of any opportunities or half-chances that may come his way.
Oscar Perez v Brian McBride
Like his American counterpart Friedel, Perez made the number one jersey his own during Mexico's qualifying campaign, beating off the challenge of Jorge Campos.
Unlike the flamobyant Campos, Perez is a far more solid stopper, whose reflexes, shot-stopping ability and positional sense makes him a goalkeeper his defenders can trust.
Perez's problem is his lack of height, and under pressure from strikers, can struggle on crosses.
McBride provides the height and physical presence in the USA forward line.
Used primarily as a target man by coach Bruce Arena, McBride is seen as the cudgel to Landon Donovan's rapier, and if the USA can get the crosses in, he will certainly be in Perez's ribs.