Three games are on the schedule in World Cup play, Belgium faces Russia in Rio de Janeiro, South Korea and Algeria clash in Porto Alegre, and the United States goes against Portugal in Manaus.
If it wins, the U.S. team will advance from Group G to the round of 16 and Portugal will be eliminated.
In another Group G match Saturday, Germany would have secured a spot in the knockout round with a win against Ghana, but they battled to a 2-2 draw. In that game, German striker Miroslav Klose scored his 15th World Cup goal, tying him with Brazilian legend Ronaldo for the most goals in World Cup history.
Also Saturday, Argentina squeeked out a 1-0 win over Iran to qualify the Argentines for the round of 16, and Nigeria kept its hopes alive of reaching the knockout round with a 1-0 win over Bosnia-Herzegovina.
Some information for this report was provided by AP, AFP and Reuters.