SAN DIEGO — On a night when the United States women should have been eyeing the upcoming Olympics, they were dealt a crushing blow to their gold medal hopes when Abby Wambach broke her left leg.

Wambach, the team's leading scorer, was carted off the field after a violent collision in the first half of a 1-0 win over Brazil last night. Wambach is expected to be out for 12 weeks and will miss the Olympics, which starts in three weeks.

Wambach, who fractured both her tibia and fibula, will have surgery today to have a titanium rod inserted into her leg.

"I want to thank all the fans, the doctors, the players on the team and Tasha Kai for scoring the winning goal," Wambach said from the emergency room. "Obviously, it's devastating, but above everything else, I'm only one player, and you can never win a championship with just one player. I have the utmost confidence in this team bringing home the gold."

Wambach is the team's leading scorer this year with 13 goals and 10 assists. She has led the team in scoring in the last three major championships and is one of the top scorers in U.S. history with 99 goals in 127 games.

"I was very emotional," U.S. captain Lindsay Tarpley said of seeing Wambach taken off the field. "She is one of my best friends."

The match, the Americans' final tuneup before they begin defense of their Olympic title, was won on Kai's second-half goal. Kai replaced Wambach on the field.

"My heart sank," said Kai, a University of Hawai'i and Kahuku High alum. "We need her. She's a big piece of a great team."

Wambach was injured during a collision with Brazilian defender Andreia Rosa. The players were going for the ball and both went down hard. Wambach began signaling the sideline almost immediately for help. She appeared to be in considerable pain as paramedics fit her with an inflatable brace before carting her off the field after 6 minutes.

"We will miss her," U.S. coach Pia Sundhage said.

Rosa got up after a minute and continued in the game.

The U.S. opens its Olympics on Aug. 6 against Norway. That title defense will now be much tougher.

"I'm excited to watch them and cheer them on during this challenge they've been presented with," Wambach said. "It's really going to take everyone coming together. I love them all so much, and appreciate so many people involved with this game and the team.

"I put my heart and soul into this game every day, but sometimes accidents happen. I've gotten so many calls already, and I just want to say how much I appreciate that."

Wambach is seeking to become just the ninth female player to reach 100 goals and the fifth American. She is also one of the most experienced U.S. players on a young squad.

Kai scored the only goal on a header in the 84th minute off a free kick from Carli Lloyd.

The win raised the Americans' 2008 record to 21-0-1 and extended their home unbeaten streak to 31. The U.S. team beat Brazil, 1-0, on Sunday at Commerce City, Colo. It was the fourth U.S. win in five matches by a 1-0 score.