SCOTTSDALE, Arizona (AP) — Japan manager Koji Yamamoto knows how difficult it will be for his country to win a third straight World Baseball Classic.

He feels his squad got off to a good start in its preparations for the semifinals.

Fighting through jet lag, Japan easily beat the San Francisco Giants 6-3 in an exhibition game Thursday.

Power-hitting first baseman Sho Nakata had three hits and second baseman Takashi Toritani added two hits and two RBIs. Four of Japan's runs came against Giants starting pitcher Yusmeiro Petit, including three in the second inning when Toritani had a two-run double.

"It is not easy to win back-to-back. We're going for our third straight, and there is a lot of pressure on our backs," Yamamoto said through a translator. "Our goal was to come here to the United States. Once we get here, anything can happen.

"We made good adjustments today (to the new, outdoor environment), especially our pitchers. I think we are in a good situation now," he said. "I think we are on track."

Japan will play another exhibition game on Friday against the Chicago Cubs in Mesa, Arizona, before heading to AT&T Park in San Francisco, where they will face the Pool 2 runner-up (either the United States, Dominican Republic or Puerto Rico) on Sunday night.

The Dominican Republic beat the United States on Thursday night, ensuring a berth in the final round. The United States must now play Puerto Rico on Friday night, with the winner earning a trip to San Francisco and the loser being eliminated.

Japan's star pitcher, Masahiro Tanaka, allowed a run and three hits and struck out three in his two-inning appearance. Eight Japan pitchers combined to allow five hits and strike out 10.

The Giants didn't field their best lineup, starting only five regulars, four of whom exited after two at-bats. But manager Bruce Bochy was impressed with Japan.

"They played well, they swung the bats well, they pitched well," Bochy said. "They played a good ballgame today. They certainly outplayed us."

Kenta Maeda, who did not pitch on Thursday against the Giants, is scheduled to start Sunday. The 24-year-old right-hander was 14-7 with a 1.53 ERA for Hiroshima in 2012, and led the league in wins, strikeouts and ERA.

Tanaka, who was heavily scouted on Thursday, is lined up to start the WBC title game on Tuesday. The 24-year-old right-hander led the Japanese Pacific League with 19 wins and a 1.27 ERA in 2011, and followed that with a 10-4 record and a 1.87 ERA in 2012 for Rakuten. There already is talk that his contract could be posted for Major League Baseball teams to bid on by next winter.

Excellent pitching is nothing new from Team Japan, who won the last two classics in San Diego and Los Angeles behind Daisuke Matsuzaka and Yu Darvish, both of whom later landed big contracts from major league teams.

But the current Japan squad differs in two areas from its championship predecessors: The only player with any major league experience is 37-year-old infielder Kaz Matsui. And while Japan's WBC numbers have been solid so far, offense could be a problem when facing the United States or the Dominican Republic.

Yamamoto said it would be more meaningful to win a third WBC title without MLB players.

"You see these guys growing with more confidence, so I think this is motivating these kids right now," he said.

"We're not worried too much about who's coming up (in San Francisco)," he said. "We try to stay focused on our team."

Japan roughed up San Francisco starter Yusmeiro Petit for four runs in four innings to beat the Giants 6-3 on Thursday in a tune-up for the World Baseball Classic semifinals this weekend.

Sho Nakata had three hits and Takashi Toritani added two hits and two RBIs for Japan.

Nakata, a power-hitting first baseman, had a run-scoring triple in the fourth, and added two singles and scored twice.

Japan used eight pitchers to limit the Giants to five hits while striking out 10.

Japan ace Masahiro Tanaka gave up three hits in two innings, yielding Francisco Peguero's one-out RBI single in the second.

Japan plays its World Baseball Classic semifinal in San Francisco on Sunday against the runner-up team in Group 2, which includes the United States, Italy, Dominican Republic and Puerto Rico.