MANAUS, Brazil - Jurgen Klinsmann will aim to summon the Super Bowl-winning spirit of his friend Pete Carroll on Sunday as the United States aims to take a step closer towards surviving the World Cup's Group of Death.

U.S. head coach Klinsmann and Carroll became pals during the Seattle Seahawks coach's time in charge of the University of Southern California and the pair developed a mutual respect.

"Impressive guy, great guy," Carroll said at Super Bowl media day back in January. "He has a great mind and I love what he is doing. I'll be watching (the World Cup)."

This tournament, where the U.S. takes on Portugal in its second group game at the Arena da Amazonia on Sunday, is the culmination of a long road of knowledge-gathering for Klinsmann.

After leaving his role as national team coach of Germany in 2006, Klinsmann, who lives in Orange County, Calif., embarked on a mission to collect as much information as possible from leading sports minds, from the world of soccer and other disciplines.

He met with Carroll at USC in 2009 and has retained contact since. Klinsmann has also attended seminars and workshops and met with Duke basketball coach Mike Krzyzewski, and Phil Jackson, an 11-time NBA champion coach

But it is from Carroll and the example of the Seahawks' swashbuckling run to the Super Bowl earlier this year that Klinsmann draws most inspiration.

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"There is an art to what Pete does that a lot of people don't see," Klinsmann told Yahoo Sports at the U.S. team's pre-World Cup training camp last month. "Just that kind of positive mindset all the time. Every detail. That kind of energy. Keeping a smile on the faces of him and the players. It is huge.

"That is what we want here, to have the players feeling good about everything they are doing. To believe in what they are doing because it has a purpose and it is working towards something bigger. From what I saw Coach Carroll is the kind of person who gives you confidence as a player.

"Look at the way his team plays. You can see it there."

Carroll has texted and Tweeted messages of good luck to Klinsmann numerous times during qualification for the World Cup and during the tournament itself.

Let's go @ussoccer!! Good luck today in Brazil! — Pete Carroll (@PeteCarroll) June 16, 2014

Best wishes to @J_Klinsmann, @clint_dempsey and the boys in their friendly tonight! #USMNT — Pete Carroll (@PeteCarroll) May 27, 2014

The Seahawks even jumped on U.S. soccer's bandwagon last year, with several players donning American jerseys before a national team game in Seattle.

An opening game victory against Ghana has put Klinsmann's men in a solid position but the Portugal matchup might be the most critical of the campaign, offering the opportunity to take a giant step toward the round of 16.

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The U.S. was widely dismissed after the draw last December, but while the path ahead is far from easy, the Ghana result opened up an avenue of hope for the team and its fervent followers.

Klinsmann, as ever, is staying positive, and stuck to the NFL theme during a recent interview with ESPN.

"Who would have said that the Seahawks win the Super Bowl at the beginning of the season?" he said. "Well they won it. Who would have said we might challenge Portugal and Germany and Ghana right away, and we make it out of the group?

"Probably not many people would say that. But I'm telling you, we're going to go for that."

Things won't get any easier for the Americans; World Cups just don't work like that. If Klinsmann can carry on the team's momentum and find a way to get out of Group G, it might not rank alongside a Super Bowl on the scale of sporting achievement, but it would probably feel every bit as good.