Klinsmann, who now faces the team he won a World Cup with as a player in 1990 and coached to the semi-finals in 2006, has spent his three years in charge of the United States attempting to push the team to a new level.
Under previous coaches Bob Bradley and Bruce Arena, the U.S. earned respect for their discipline, aggression and determination but the German has succeeded in producing a team that keeps all those qualities while playing a high-tempo passing game.
Klinsmann drew criticism for his squad selection for the tournament, particularly leaving out his team???s record scorer Landon Donovan, but his focus on picking players who are quick and have great stamina, has paid off.
The German has been relentless in repeating his mantra about tempo throughout the team???s training camp, where he focused heavily on physical conditioning, and throughout the early stages of the tournament.
???I think the team has shown amazing progress throughout the last couple of weeks. We???ll build on everything we worked on. It???s been more than five weeks, and you see more and more the quality and results coming through that building process.
"The way we controlled most of the game against a very strong Portuguese side is telling you how far we made it already,??? said Klinsmann.
"I think everything we talked to over the last weeks came into place. Unfortunately, we had that early goal against, but then it was us controlling the game, setting a tempo and coming back and also having enough chances to score three or four goals, and that's what we've got to build on.
"We take even more confidence now into the next game, and it's going to be another final, but that's what the World Cup is about,??? he said.
Two of the German-Americans that Klinsmann has integrated into his team, midfielder Jermaine Jones and overlapping full-back Fabian Johnson, were outstanding against Portugal while Clint Dempsey was tireless and aggressive in attack.
Defensive midfielder Kyle Beckerman, ignored by Bradley for the World Cup four years ago, has been the anchor of the midfield and has rewarded the faith Klinsmann has shown in a 32-year-old who has played his entire career in Major League Soccer.
The central midfield trio of Beckerman, Jones and Michael Bradley were relentless in closing down space and intelligent in their use of the ball ??? at least until Bradley was robbed of posssession in the final seconds allowing Portugal to unleash their fatal final counter-attack.
Goalkeeper Tim Howard said credit deserves to go to that central threesome and to Klinsmann for his tactical approach to the game.
???Coach Klinsmann and his staff had an exquisite game plan. I thought we executed it brilliantly. Portugal didn???t hurt us really. I think we had the better passage of play. You look at two goals that realistically can be prevented. It???s not as if they opened us up and sliced us open. We contained them pretty well," said the keeper.
"Football is cruel sometimes but we???ve got a great chance in ???the group of death??? to go through and advance. We???re excited.???