American star Clint Dempsey celebrates scoring his side's third goal in a 4-3 win over Germany at RFK Stadium on Sunday. (Dennis Grombkowski/BONGARTS/GETTY IMAGES)

RFK Stadium was still pulsating from an entertaining if imperfect friendly Sunday, a 4-3 U.S. victory over Germany that capped American soccer’s centennial celebrations.

But Juergen Klinsmann’s national team had to quickly pivot from a fun and productive outing before a sellout crowd of 47,359 to more consequential endeavors over the next two weeks.

“Now the road gets long,” goalkeeper Tim Howard said.

The road begins Friday in Jamaica for the first of three World Cup qualifiers over 12 days — games that will go a long way toward determining whether the Americans secure passage to Brazil next summer. The United States (1-1-1) is third in a six-nation regional group vying for three automatic berths.

After a 4-2 friendly loss to Belgium four days earlier, the Americans made notable strides against Germany by scoring three terrific goals. They also took advantage of a comical error by the German goalkeeper.

Jozy Altidore volleyed his way out of a scoring funk and assisted on the first of Clint Dempsey’s two second-half goals. Dempsey raised his international scoring total to 35, second on the U.S. charts behind Landon Donovan’s 49, and continued to build chemistry with Altidore.

“That is what a striker needs — a striker needs goals to feel good about himself,” Klinsmann said of Alitdore, who scored a U.S.-record 31 times for his Dutch club this season.

The quality attack was almost offset by another rickety defensive performance in the second half.

Like against Belgium, the United States conceded three goals after intermission.

With their team trailing 4-1, Max Kruse and Julian Draxler struck in the 79th and 81st minutes.

Germany, which was missing eight Bayern Munich stars and two Real Madrid standouts, pressed for the equalizer, but referee Paul Delgadillo of Mexico ignored a penalty kick plea in the 90th minute.

The outcome provided a boost to a U.S. team that has experienced growing pains since Klinsmann’s appointment almost two years ago.

“Morale, motivation, the feel-good factor, all of that is going to play a huge role,” Howard said. “I don’t think that can be understated because going down to Jamaica is not going to be easy.”

Altidore’s drought ended in the 13th minute. Graham Zusi served a delicious cross from the right flank to the heart of the penalty area. Altidore was unmarked and unfazed, smashing a 10-yard volley for his first U.S. goal since a friendly in Slovenia in November 2011.

“I honestly feel like I have been doing the right things,” Altidore said. “It’s just a matter of being patient and waiting for the chances.”

Famous for impeccable composure, Germany blundered three minutes later.

Under moderate pressure deep in their own end, the Germans failed to find an escape route. Bendikt Hoewedes decided to play the ball back to goalkeeper Marc-Andre ter Stegen. Distracted by Jermaine Jones’s presence, ter Stegen let the ball slip past him and into the net.

Just 21, ter Stegenº started the past two seasons for Moenchengladbach in the famed Bundesliga and was making his third national team appearance.

“My team was sleepy at times,” Germany Coach Joachim Loew said.

The goalie had another clownish experience midway through the half when, backpedaling on Altidore’s ambitious floater from 40 yards, he tumbled. To his relief, the attempt was off target.

After Heiko Westermann’s six-yard header early in the second half, Dempsey struck twice. On the first, he met Altidore’s bouncing cross and tagged an 11-yard shot into the left side. Five minutes later, in a seemingly harmless position, he began toying with Lukas Podolski, carved a pocket of space and then unleashed a swerving, 25-yard rocket to the upper left corner.

Germany’s uprising caused late angst, but the Americans ended their qualifying preparations with an uplifting result.

“We take confidence from this game and we have got to make sure we get the job done in these next three games,” Dempsey said. “Whether we won these two friendlies, not won these two friendlies, it all matters what we do in these next three games. That is what it is all about.”

U.S. notes: The turnout was the largest for soccer at RFK since David Beckham’s MLS regular season debut in 2007 and the fourth biggest to see the U.S. senior national team. The soccer record is 58,012 for a 1996 Olympic group match between the United States and Portugal. (At the time, the Redskins were still playing there and the facility accommodated more spectators.)