From the perspective of Women's World Cup organizers, the U.S. women's national soccer team has had a perfect run through the tournament. The Americans have advanced to Sunday's semifinal here against Brazil. They've filled stadiums or drawn near sellouts. Their matches have been replete with goals. And, on a few occasions, they've generated nerve-rattling excitement because of early lapses by U.S. defenders.

It's the latter part of that equation that U.S. Coach Tony DiCicco could do without. In three of its four victories, the United States has been threatened seriously, or scored upon, in the opening minutes because of inexplicable breakdowns.

"We can't keep playing that game of Russian roulette," forward Mia Hamm said, "because sooner or later you're going to get the bullet."

Against the high-powered, offense-oriented Brazilians, who are led by the tournament's leading goal scorer, Sissi -- who has seven goals in four games -- the Americans cannot afford the giveaway goals or near calamities that have characterized two of their four victories.

"I'm concerned," DiCicco said after Thursday's 3-2 quarterfinal victory over Germany at Jack Kent Cooke Stadium. "I'm very concerned."

Players say opening-match jitters and random bad luck have played a part in the mishaps. Two minutes into the U.S. team's opening 3-0 victory over Denmark, Gitte Krogh got behind the U.S. defense and barely missed giving her team a 1-0 lead. When the U.S. team faced Nigeria in the next game, Nkiru Okosieme did score in the second minute, after U.S. defenders failed to clear a loose ball in the penalty area. Minutes later, Nigeria nearly scored again when two U.S. defenders collided like the Keystone Cops in front of the goal.

The biggest scare came in Thursday's come-from-behind victory over Germany. U.S. defender Brandi Chastain and goalkeeper Briana Scurry miscommunicated and Chastain accidentally kicked a ball into the U.S. goal in the game's fifth minute, giving Germany a 1-0 lead. Two minutes earlier, Joy Fawcett, who scored the game-winning goal in the second half, tapped a header too softly to Scurry. The ball was nearly stolen by a German player and sent in for an even earlier score.

"This is the World Cup and we're playing the best players in the world," Chastain said. "Just because the stage is so large and you don't expect [an error] to happen to the best players, it does. We're human."

U.S. assistant coach Lauren Gregg suggested that the Americans might open the semifinal with a different defensive approach designed to diffuse players' early energy -- perhaps caused by nervousness or overflowing adrenaline. Thus far in the tournament, the U.S. team has opened its games playing a pressurized defense over three-quarters of the field, which, in essence, gives teams a bit of breathing room to get their attack underway. In the second half Thursday, the U.S. team switched to a full-field pressure defense, and the Germans failed to score.

"It's really been team breakdowns," said Gregg, who formerly coached the women's team at the University of Virginia. "The onus of the breakdown starts earlier. We're not pressuring the ball, the midfield is sagging. . . . I think you may see a bit of a different start to the next game defensively."

Defensive lapses are the greatest fear of a team that attacks as much as the Americans do. DiCicco, though, would sooner concede the tournament than take the aggressiveness out of his lineup, which has provided offensive punch from nearly every position on the field.

Ten U.S. players have scored in the first four matches, which the Americans have won by a 16-3 margin. Tiffeny Milbrett leads with three, and Mia Hamm, Kristine Lilly and Tisha Venturini have two each. Cindy Parlow, Julie Foudy, Michelle Akers, Shannon MacMillan, Chastain and Fawcett have one each. The U.S. benefited from one own goal in its 7-1 victory over Nigeria. The only American starters who haven't scored are Scurry and defenders Carla Overbeck and Kate Sobrero.

So while the United States has significant defensive concerns for Sunday's game, it can be sure the Brazilians are equally worried.

"The United States is a team with no weakness," Brazilian Coach Wilson Oliveira Rica said after his team's win over Nigeria Thursday. "It's a well-trained, fit and balanced team.

"But," Oliveira Rica added, "we are certain that this match will be the best of the Cup to date."

Schedule

Sunday's

semifinals

In Palo Alto, Calif.

United States vs. Brazil

Kickoff: 4:30 p.m.

TV: ESPN

In Foxboro, Mass.

China vs. Norway

Kickoff: 7:30 p.m.

TV: ESPN2

Third Place, July 10

In Pasadena, Calif.

Kickoff: 1:15 p.m.

TV: ESPN

Final, July 10

In Pasadena, Calif.

Kickoff: 3:50 p.m.

TV: ABC