Turning to two teenagers with the Williams sisters injured, the United States is on the verge of being knocked out of the World Group for the first time after losing both singles matches to Germany in a Fed Cup playoff Saturday.

Andrea Petkovic defeated 18-year-old Christina McHale 6-3, 6-4 in the opening singles, and Julia Goerges beat 19-year-old Melanie Oudin 6-2, 7-6 (5). Germany is within a point of capturing the best-of-five series on indoor clay, with reverse singles and doubles Sunday.

"I am very proud of both of them, they did as much as possible," U.S. captain Mary Joe Fernandez said. "We'll try to be better tomorrow, it's been done before, coming back from 2-0 down."

In the semifinals of the World Group, the Czech Republic and Belgium are 1-1 at Charleroi, Belgium, and Russia leads Italy 2-0 in Moscow. The winners play for the title Nov. 5-6.

The Americans have won the Fed Cup a record 17 times and have never been relegated to a lower tier. The U.S. was the Fed Cup runner-up in the last two years, losing both times to Italy.

Venus Williams cheered her teammates from the stands at Porsche Arena. She has a hip injury but traveled to Germany to be eligible for the 2012 London Games. Players are to make themselves available for the Fed Cup to play in the Olympics. Serena Williams has had two foot operations and a blood clot in her lungs.

The U.S. also was without Fed Cup regular Bethanie Mattek-Sands, who has an ailing hip.

McHale started strongly, staying with Petkovic at 3-3 before dropping the set. In the second set, the 19th-ranked Petkovic led 4-0. McHale rallied within a game but the German served out the match. McHale said the seventh game of the first set was the turning point.

"It changed the momentum a little bit, there was a stretch when I was in the match but could not win a game. I was happy I was able to compete better in the second," she said.

Petkovic saved three break points and won seven straight games to take command.

"I've seen her play in the United States, she has beaten some top 10 players so I knew what to expect," Petkovic said. "She played really well until then, but she then lost her focus a little. That's inexperience, but she can play really well."

McHale just reached a career-high ranking of No. 82.

Goerges rolled through the first set but had a harder time finishing it off in the second. Oudin nearly came within a point of set point. A shot by Goerges was called long and would have given the American a 6-5 lead in the tiebreaker. But the chair umpire inspected the mark and overruled.

Goerges, who recently lost to Oudin in Miami, won the last two points to close the match.

"When someone serves like that there is not much you can do and it puts pressure on your serve," Oudin said. "I've never seen her serve that well."

Germany coach Barbara Rittner is glad her team has a chance to wrap up the series in singles.

"The U.S. always has very good and experienced doubles, and I'd love to have it decided in the singles," Rittner said. "We had two pretty close matches, both Christina and Melanie gave us a good challenge."