The World Cup round of 16 in Brazil is taking shape.

Already in: Argentina, Chile, Colombia, Costa Rica and the Netherlands. The big question: Will the United States join that distinguished list today?

The U.S. soccer team has a tough matchup against Portugal. Win, and the Americans are in. Lose or tie, and the road gets a lot tougher with next Thursday's game against Germany.

The U.S. is playing in the so-called "Group of Death" paired with Germany, Portugal and Ghana. Germany is No. 2 in the world. Portugal is ranked fourth, and Ghana eliminated the United States from the past two World Cups. But last Monday, the U.S. squad defeated Ghana 2-1 and Germany embarrassed Portugal 4-0. On Saturday, Ghana and Germany played to a thrilling 2-2 tie.

Many people had counted the U.S. out of the World Cup before it began, but so far, the ball has bounced the team's way. Even Portugal's star player (and reigning world player of the year) Cristiano Ronaldo is hobbled by tendinitis in his left knee.

At a pre-game news conference on Saturday, U.S. Coach Jurgen Klinsmann said this is his team's time. "This is now the moment where you can prove yourself," he said. "This is the moment where you can step up and play those guys and put them in place."

No easy task, though, as NPR's Tom Goldman reports for our Newscast desk:

"A loss by Portugal and it's out, meaning this isn't going to be boring. In a World Cup where stars have played up to their billing, U.S. goalkeeper Tim Howard knows it's important to keep a close eye on Portugal's great forward Cristiano Ronaldo, who's starting despite recent knee troubles."

"We're going to do our best to bottle him up," Howard said. "It's not been done in four or five years. But we'll see what we can do."

The Americans know, however, that paying too much attention to Ronaldo could let someone else beat them.

It may not be someone on the field that's the biggest challenge: It could be the weather. The game is in Manaus, in the heart of the Amazon jungle. It is winter, but it's still steamy, sticky and rainy.

Oh, and there are mosquitoes too. People traveling here have been warned to take malaria pills and get vaccinated for yellow fever.

Copyright 2016 NPR. To see more, visit