After escaping Group G on goal difference from Portugal Klinsmann's men now face a tough second round tie with Belgium, but the German is confident they have prepared for what is about to come.
Two of the five completed matches in the round of 16 have gone to extra-time, and then penalties, something the 49-year-old insists his players are looking forward to if it happens in Salvador.
Klinsmann believes the squad are hungry to go further in the competition than ever before, and hopes to cause an upset on Tuesday.
"Going into the knockout stage you need to have a team ready to go the extra mile," he told a news conference on Monday. "Every single player needs to be ready to go 120 minutes and possibly a penalty shooutout, so it is very very demanding.
"It's the most extreme version you can have as a player going into those games, but that's what we're looking forward to, that's why we worked very hard to build a foundation for this moment.
"A lot of the games are decided in the last minutes, some are in penalty shootouts, hopefully we have everything in our legs to go 120 minutes if necessary.
"I'm very positive we have a good foundation for getting everything out of Belgium.
"The better team should win and go forward, but we're doing well, we feel fresh, we feel recovered quickly, we have a great spirit and it feels like we just started this adventure.
"We are hungry, hungry for more, and we want to prove that to the best of our capabilities tomorrow night."
USA's best World Cup showing was a quarter-final run in 2002, a feat they wre prevented from emulating by Ghana in the round of 16 four-years ago.
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