The Mexicans take on Guatemala on Saturday at the New Meadowlands stadium in New Jersey, while the U.S. face improving Jamaica at the RFK stadium in Washington D.C. on Sunday.
Mexico, clear favourites for a sixth Gold Cup title, have been in sparkling form so far, winning all three of their group games, scoring 14 goals in the process and conceding just one.
Manchester United striker Javier Hernandez has been in devastating form with five goals for El Tri including a hat-trick in the opening day 5-0 thrashing of El Salvador.
With Andres Guardado and Giovani dos Santos playing in support of the poacher Hernandez, Mexico have by the far most potent attack in the tournament, scoring twice as many goals as any other team in the group stage.
All this has been achieved despite the loss of five players from the Mexico squad after it was discovered they had tested positive for the banned substance Clenbuterol.
Guatemala are an improving team with some exciting talent, including winger Marco Pappa, and their coach Hugo Almeida said they should not be underestimatedr.
"I don't know why they are counting us for dead. We are very much alive," he said.
"It is true that Mexico is the powerhouse here but when you play a team like that you tend to try even harder. We respect Mexico but we have some fast young players and we will see how we go."
The United States, who met Mexico in the last two Gold Cup finals including a 5-0 defeat in 2009, are hoping for a return to their best form after some drab displays so far.
Bob Bradley's side were solid but uninspiring in a 2-0 win over Canada, flat and lacking composure in their shock 2-1 loss to Panama and couldn't finish off tiny Guadeloupe as they picked up the bare minimum expected with a 1-0 win.
After those disappointing performances, the team's two top attacking threats, Landon Donovan and Clint Dempsey, have been given permission to miss the three days of training in the build-up to Sunday's clash in order to attend the weddings of their respective sisters.
The U.S. are up against a Jamaican team who won all three of their group stage games, including an impressive 1-0 win over 2010 World Cup finalists Honduras.
Under coach Theodore Whitmore, the Reggae Boyz have come together as a team unit again after a poor World Cup qualifying campaign and with Dane Richards and Ryan Johnson provided pace and skill up-front they will be a tough opponent for the U.S.
Jamaica have never beaten the U.S however, losing nine of the 17 meetings of the two nations including seven of nine on U.S. soil.
Panama showed the U.S was susceptible to pace and aggression and the Panamanians are looking to progress further when they face El Salvador in the capital on Sunday.
The other tie is a classic Central American match-up with Costa Rica, who suffered a 4-1 thrashing from Mexico, taking on Honduras.
