Two-way star Shohei Ohtani struck out 10 in six scoreless innings and left with a one-run lead, but his Los Angeles Angels lost to the Oakland Athletics 2-1 on Thursday's MLB Opening Day.
Japanese compatriot Masataka Yoshida, meanwhile, went 2-for-4 with an RBI in his major league debut in the Boston Red Sox's 10-9 loss to the Baltimore Orioles.
Ohtani allowed just two hits while walking three in a 93-pitch outing at Oakland Coliseum.
The World Baseball Classic MVP faced runners on second and third with one out in the fourth inning, but escaped the jam by striking out two straight batters.
"I walked the first batter I faced, but I managed to find my rhythm on the mound," Ohtani said. "We wanted to score an additional run. We didn't get a hit when we needed it."
The Athletics turned the game around in the eighth, with Tony Kemp's double and Aledmys Diaz's single driving in one run each.
At the plate, Ohtani singled in the fourth and finished 1-for-3 with an intentional walk and two strikeouts.
Yoshida's first hit, a single up the middle in the sixth inning off left-handed reliever Keegan Akin, scored Rafael Devers from second base to cut the Orioles' lead to 8-3 at Fenway Park in Boston.
Yoshida, batting cleanup and playing left field, added a single to right in the eighth.
"I'm relieved rather than happy," the 29-year-old said of his first two career hits. "I was deeply touched when I heard the U.S. national anthem. I'm not satisfied by just being on this stage, but I have to thank many people."
Yoshida, a two-time batting champion with the Orix Buffaloes in the Pacific League, signed a five-year, $90 million deal with the Red Sox, the highest ever for a Japanese position player when making the move from Japan to the United States.
Adley Rutschman went 5-for-5 with a homer and four RBIs for the Orioles.
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