Japan roughed up San Francisco starter Yusmeiro Petit for four runs and six of its 11 hits in four innings, beating the Giants 6-3 on Thursday.
Sho Nakata had three hits, and Takashi Toritani added two hits and two RBIs for Japan, tuning up for its appearance in the World Baseball Classic semifinals in San Francisco on Sunday. Toritani had a two-run double in Japan's three-run second inning.
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.
The Giants' lineup included key regulars Marco Scutaro, Pablo Sandoval, Buster Posey and Hunter Pence for only two at-bats apiece. San Francisco used five relievers following Petit.
Japan ace Masahiro Tanaka gave up three hits in two innings, yielding Francisco Peguero's one-out RBI single in the second.