The United States men’s national team have already exceeded outside expectations by coming through the much-discussed “Group of Death,” but they show no signs of being content with their achievements in Brazil. Jürgen  Klinsmann wants the USA to think like and become a major soccer nation, and that means seeing the group stage as just the appetizer of the World Cup feast.

Hours after being defeated by Germany in Recife but having their progress confirmed thanks to Portugal’s win over Ghana, the U.S. discovered the identity of their opponents. Standing in the way of the U.S. matching its best performance in the World Cup since 1930 by reaching the quarterfinals will be a Belgium side, which finished with a perfect record in their group and came into the competition as the most hotly tipped of dark horses.

Klinsmann, who went to the knockout stages of a World Cup with Germany three times as a player and once as coach, is as equipped as any to understand that the real tournament is only just beginning.

"Obviously it is a huge achievement by our team to come through that group and qualify,” Klinsmann said after the loss with Germany, according to Reuters. “We knew it was going to be a tricky game and it was not so easy to handle it mentally,”. “We had a little bit too much respect at first.

“I screamed as much as I could at them to push further up but that is easier said than done. But whoever we face now, we are going to take it to them. Now we can put this behind us and, as we know, when the group is done, another tournament starts and that is a whole other ball game.”

Klinsmann will be all too aware that his side can and need to improve if their World Cup is to extend much further. An opening win over Ghana ultimately proved crucial in securing their progress through the group stage, but it was a match when the U.S. won largely thanks to a trademark backs-against-the-wall effort; the type of performance that Klinsmann has been keen to end as the team’s trademark. Undoubtedly the best U.S. performance thus far came against Portugal. A goal down early on, they were forced to be proactive and subsequently displayed their greater comfort in taking the ascendency that Klinsmann has worked hard to introduce.

In the final game against Germany, the U.S. again struggled in possession, although with the caveat that they appeared jaded from their exertions in Manaus in the previous game. The best performers for the team so far in Brazil have been those with defensive roles. Matt Besler has hardly put a foot wrong in the center of defense, while Jermaine Jones and Kyle Beckerman have been excellent in holding down the midfield. But the star man coming into the tournament Michael Bradley has yet to show his quality going forward, while the attack has been hampered by an injury to Jozy Altidore.

The encouraging aspect is that, having produced possibly the biggest achievement in the history of U.S. soccer and riveted a huge percentage of the country along the way, the U.S. can still do better.

There is reason to think that the U.S. team’s World Cup won’t end in Salvador on Tuesday. Despite their impressive results, Belgium have far from justified their billing as fifth favorites to lift the trophy before a ball was kicked.

It is undoubtedly a fine generation of players that Belgium has at its disposal and there are some genuine game-changers. A player of the world-class quality of Chelsea’s Eden Hazard has yet to be produced in the United States, and it could ultimately be that which decides what should be a tight affair.

Thus far, however, the team led by former forward Marc Wilmots has been almost completely reliant on moments of individual brilliance. Hazard and Napoli’s Dries Mertens have produced flashes of magic in wins over Algeria and Russia, while they battled to get a 1-0 win over South Korea with 10 men, but there has been little cohesive system to the team as a whole.

If Hazard and his fellow attacking midfielders can be shut down, not an easy job by any means but the type that the Americans should relish, then the U.S. has a real chance to match their achievement of 2002. 

Prediction: USA 1-0 Belgium

When and where: The Round of 16 match at the 2014 World Cup will kick off from the Arena Fonte Nova in Salvador at 4 p.m. ET.