LOS ANGELES — For the second time in three years, the United States was beaten at its own game on its own turf.

Maybe baseball just ain't America's sport anymore.

Daisuke Matsuzaka remained undefeated in the World Baseball Classic and defending champion Japan topped Team USA, 9-4, in the semifinals at Dodger Stadium last night.

"Can you believe this? Look at the score. I feel so bad about this," Tom Lasorda, Hall of Fame manager and WBC global ambassador, said.

"I'm very, very disappointed. We had high hopes. This is the second time we were supposed to win. We taught these people the game."

Instead, Japan, which rallied from a 2-1 deficit in the fourth inning, gave the lessons on American soil

Matsuzaka sent his country into tonight's title game against South Korea, a 10-2 winner over Venezuela in Saturday's semifinal. Japan won the inaugural tournament in 2006, defeating Cuba in the final.

Akinori Iwamura's RBI triple was the key hit in a five-run fourth inning against starter Roy Oswalt, and the U.S. absorbed its first loss to Japan in major international play since the 2005 World Cup. The Americans had won four in a row, including an 8-4 victory in the bronze medal game at the Beijing Olympics.

"We didn't play as well defensively," U.S. manager Davey Johnson said. "We made it a ballgame through seven innings, and made some mistakes, walked the leadoff hitter in the eighth, and that's not the way you win ballgames."

Matsuzaka allowed two runs and five hits in 4 2/3 innings. The Boston Red Sox right-hander struck out four and walked three before being pulled when he reached 98 pitches, two shy of the 100-limit for the tournament's final two rounds.

Matsuzaka, who pitched six shutout innings against Cuba last Sunday, is 3-0 in this year's WBC, having allowed 14 hits and four runs in 14 2/3 innings. He went 3-0 and was selected tournament MVP three years ago.

Meanwhile, Oswalt got tagged, giving up six runs and six hits in 3 2/3 innings. He walked four and struck out one. The Houston Astros right-hander was 1-1 in three WBC starts, allowing nine runs, seven earned, in 11 1/3 innings.