Taylor Trammell homered for Seattle, which had won three out of four and 10 of 14 since starting the season 11-16. Luis Castillo (2-2) allowed seven runs — five earned — on six hits and two walks while striking out six in five innings.
Yoshida tripled and Turner and Casas homered in Boston’s four-run first. But Seattle tied it in the fourth, thanks in part to Teoscar Hernandez’s sinking liner to center that Duran dove for and missed; the ball rolled past him toward the wall.
“He’s trying to make a baseball play. I’d rather have that than lack of effort,” Red Sox manager Alex Cora said. “He’s in a great place. He’s going to make mistakes, but overall his game has been a plus everywhere.”
Trammell followed with a two-run homer to make it 4-4. Alex Verdugo doubled leading off the bottom of the fifth, and Yoshida’s one-bounce, ground-rule double in the right field corner broke the tie. The Japanese left fielder took third on a flyout and scored on Castillo’s wild pitch before Duran homered for a 7-4 lead.
Duran singled in another run in the seventh and improved to 7 for 7 on stolen bases.
“He’s a game-changer,” Turner said. “He’s got power. He’s got speed. He uses the whole field and plays great defense in the center. So it’s good to see him having success hitting the ball all over the place and running the bases like it is.”
Yoshida made it 9-4 in the eighth on a bases-loaded groundout.
The Red Sox put RHP John Schreiber on the 15-day injured list with a right shoulder strain.
The teams wrap up the three-game series, with Boston RHP Brayan Bello (2-1) set to start against lefty Marco Gonzales (3-0).