BRATISLAVA, Slovakia -- Twins Mike and Bob Bryan made their Davis Cup debut Saturday, winning a doubles match against Slovakia that left the United States one victory from capturing its playoff.

They defeated Karol Beck and Dominik Hrbaty 6-1, 6-4, 7-6 (5) on clay to give the Americans a 2-1 lead in the best-of-five series.

"I feel a tremendous sense of relief that these two guys are on our team now," captain Patrick McEnroe said. "They are our doubles team in my mind no matter what happened today."

A victory in Sunday's first singles by U.S. Open champion Andy Roddick against Karol Kucera would keep the United States in the elite 16-team World Group. If Slovakia wins both singles, the Americans drop to the Davis Cup's second tier for the first time in 15 years.

Mardy Fish faces Hrbaty in the second singles. The Americans are 60-9 when leading 2-1 entering the final day.

The United States has won a record 31 Davis Cup but the last was eight years ago.

In the Davis Cup semifinals, Argentina won its doubles but trails Spain 2-1 in Malaga, and Australia leads Switzerland 2-1 following the Aussies' five-set doubles victory in Melbourne.

The Bryans, 25-year-old identical twins from California, are the 22nd tandem the United States has tried since 1992. The two are the world's No. 1-ranked doubles team and this year's French Open champion. Mike is two minutes younger, a right-hander and 6-foot-3; Bob is a left-hander and 6-4.

They look like mirror images on the court and seldom miss the other's cues. By comparison, the Slovak team rarely plays together. Hrbaty was substituted for by Michal Mertinak an hour before the match.

"We knew they hadn't played much together," Mike said. "We rarely let a ball go between us, and that's our advantage. We play together every week, every day."

The Bryans dominated the match, although the Slovaks had eight break points -- one was a set point -- and didn't convert any. They also fended off four match points before the Americans prevailed in the tiebreaker.

"It wasn't going to come easy in our first Davis Cup match," Bob said. "I knew it was going to be tough playing overseas ... I felt pretty good getting up 6-1, but then we had to pull it out."

The Bryans are the first siblings to represent the United States since George and Robert Wrenn in 1903. The only others were John and Patrick McEnroe. They were on the 1983 team but Patrick was a practice player and did not compete. The Wrenn brothers teamed in doubles 100 years ago.

Roddick was upset in singles Friday by Hrbaty -- his third straight loss in Davis Cup, all on clay -- but can atone Sunday. Kucera is expected to play, although captain Miloslav Mecir suggested he might use Beck.

The loss snapped Roddick's 19-match winning streak, all on hard courts and all in North America.

"I don't think I'll have to say much to Andy tomorrow," McEnroe said. "I think he's going to be a different player. He's in a much better frame of mind. He was a little edgy yesterday."

The Americans have lost three straight Davis Cup matches on the road since Patrick McEnroe became captain in 2001 and four straight overall. The last loss was in Croatia in February.

John McEnroe was captain for the other away loss. The most consecutive road losses for a U.S. team is five.

In other best-of-five playoffs, it was: Zimbabwe 3, Italy 0; Luxembourg 3, Norway 0; Netherlands 3, India 0; Venezuela 3, Bahamas 0; Taiwan 3, Hong Kong 0; Belarus 2, Germany 1; Romania 2, Ecuador 1; Austria 2, Belgium 1; Canada 2, Brazil 1; Czech Republic 2, Thailand 1; Morocco 2, Britain 1; South Africa 2, Denmark 1; Greece 2, Serbia-Montenegro 1; and Pakistan 2, South Korea 1.