Midfielder Graham Zusi, left, and the United States are looking to rebound from a loss to Belgium with a friendly match against Germany on Sunday at sold-out RFK Stadium. (Tony Dejak/AP)

The U.S. Soccer Federation is celebrating its centennial this weekend in Washington with parties, galas and meetings leading to a high-caliber friendly featuring the men’s national team against Germany on Sunday afternoon at sold-out RFK Stadium. Hundreds have gathered to toast the anniversary and salute landmark feats, most of which were achieved in the past quarter-century.

As USSF President Sunil Gulati said, “We stand in a better place than the sport has ever been.”

He is correct. For all the strides, though, casual observers ultimately will measure American soccer by whether the team qualifies for the World Cup and how it fares on the grandest stage. The United States has partaken in six in a row, with varying degrees of success.

The weekend jamboree comes at a critical stage in the pursuit of a seventh consecutive berth. Under Juergen Klinsmann, who set out to modernize the U.S. system, the Americans are enduring growing pains. They have won notable away friendlies (Italy and Mexico, among them) but have suffered missteps on the road to the World Cup in Brazil next summer.

“We’re trying to raise the bar, one step at a time — sometimes two steps backwards and then hopefully three in the right direction,” Klinsmann said before Saturday’s training session in front of more than 2,000 at RFK. “It’s a development that comes with some hiccups.”

With three of 10 games done, Klinsmann’s crew is third among six teams vying for three automatic berths from the CONCACAF region. (A fourth side will enter a special playoff in the fall against the Oceania winner.)

After losing in Honduras in February, the Americans (1-1-1) defeated Costa Rica in a Colorado blizzard and earned a tie in Mexico City, where they’ve never won a qualifier.

Last year they needed a comeback victory on the last day of the semifinal round to secure passage to the final stage.

“We are still trying to get there,” midfielder Clint Dempsey said. “We are not where we want to be.”

The Germany test precedes three qualifiers over 12 days: Friday at Jamaica (0-1-2), June 11 against Panama (1-0-2) in Seattle and June 18 against Honduras (1-1-1) in suburban Salt Lake City.

Preparations began poorly Wednesday with a 4-2 loss to Belgium in Cleveland, rekindling concerns about the team’s direction.

The arrival of midfielder Michael Bradley and defender Fabian Johnson bolstered Klinsmann’s roster ahead of the Germany game.

“There is definitely some urgency” with the qualifiers approaching, midfielder Graham Zusi said, “but there is an urgency to get back on the field as well to make up for some wrongs.”

Although the Germany match is non-binding, it does offer several intriguing story lines:

●Klinsmann is coaching against his birth nation for the first time. He is tied for third on Germany’s scoring charts with 47 goals and fourth in appearances (108). He played in three World Cups, raising the trophy in 1990, and was the first player to score in three European Championships.

On the club level, he starred for Stuttgart and Bayern Munich.

As a coach, he oversaw Germany’s third-place finish at the 2006 World Cup on home soil and had a brief, contentious stint with Bayern in 2008-09. Joachim Loew, Klinsmann’s top assistant and tactician, has managed Germany for almost seven years.

Klinsmann and Loew reconnected at the U.S. team hotel Friday night.

“It was a very emotional meeting,” Loew said. “We took a trip down memory lane.”

●Klinsmann has never coached at RFK but has played there: Next week is the 20th anniversary of him scoring twice in Germany’s three-goal, second-half comeback during a 3-3 draw with Brazil in the U.S. Cup tournament. In 2001, he donned a D.C. United jersey in a benefit game.

●Fabian Johnson, Jermaine Jones, Danny Williams and Terrence Boyd were born and reared in Germany to American servicemen and chose to represent the United States. Timothy Chandler has a similar background but missed this camp with a knee injury. Jones played in three friendlies for Germany before exercising an option to switch allegiances. All five are employed by Bundesliga clubs.

●Unlike the Americans, Germany is not prepping for World Cup qualifiers and, combined with club conflicts, the core of the squad was not available. Eight national team players remained with Champions League winner Bayern Munich for the German Cup final Saturday against Stuttgart. Real Madrid midfielders Mesut Ozil and Sami Khedira concluded their Spanish season Saturday.

The most prominent German player on location is Miroslav Klose, who joined the club following a 4-2 victory over Ecuador on Wednesday in Boca Raton, Fla. Klose, who turns 35 next week, is one goal short of tying Gerd Mueller’s national team record (68), which has stood for 39 years. With 14 World Cup goals, he is tied for second with Mueller behind Ronaldo of Brazil (15).

“We are going to give them a real good game,” Klinsmann said. “Most importantly, we want to go into Jamaica and get three points and a possible nine points in the three qualifying games. That is where our focus really is.”

U.S. notes: Temporary bleachers were erected behind the goals, boosting capacity to about 46,000. For MLS matches, those areas are used for promotion and hospitality. . . . The U.S. team is 13-3-5 at RFK and unbeaten in the previous seven visits (6-0-1). . . . The USSF finalized a July 5 friendly against Guatemala in San Diego. It will serve as the last tuneup before the CONCACAF Gold Cup. An Aug. 14 friendly in Europe is also in the works, with Bosnia as the leading candidate. . . . Because of the hot weather, security will allow each fan to bring one 20-ounce bottle of water (unopened) into the stadium.