Tim Beckham hit two of Seattle's five home runs as the Mariners defeated the visiting Boston Red Sox 12-4 Thursday night.
Boston allowed the most runs ever by a defending World Series champion in its season opener, according to ESPN.
Edwin Encarnacion, Ryon Healy and Domingo Santana also homered for Seattle, which improved to 3-0 after sweeping a two-game series against Oakland in Tokyo last week.
Mariners left-hander Marco Gonzales (2-0) got the win despite allowing four runs (three earned) on nine hits in 5 1/3 innings. He struck out four and issued one walk.
Red Sox starter Chris Sale (0-1) yielded seven runs on six hits in three innings. He walked two and struck out four. The seven runs matched the most Sale has allowed since joining Boston in a December 2016 trade from the Chicago White Sox.
The Red Sox scored in each of the first two innings against Gonzales on an RBI single by J.D. Martinez and a sacrifice fly by Andrew Benintendi.
The Mariners responded with three runs in the bottom of the second and four more in the third off Sale.
With one out in the second, Beckham hit a 430-foot shot into the second deck in left field. With two outs and the bases loaded, Santana doubled down the right field line to give Seattle a 3-2 lead.
Encarnacion led off the bottom of the third with a home run. After a one-out walk to Healy, Beckham went deep to straightaway center field. A triple by Mallex Smith and a sacrifice fly by David Freitas made it 7-2.
Healy led off the bottom of the fifth with solo shot to make it 8-2.
The Red Sox scored twice in the sixth on doubles by Eduardo Nunez and Christian Vazquez and a two-out single by Benintendi, the latter hit off left-handed reliever Roenis Elias.
The Mariners got those runs back in the bottom of the inning a bases-loaded walk and a two-out error by second baseman Nunez.
Santana hit a two-run homer in the seventh, giving him four RBIs for the second time in three games.
Elias and right-handers Cory Gearrin and Brandon Brennan combined for 3 2/3 scoreless innings of relief, allowing two hits and no walks with four strikeouts.