Luis Castillo delivered his sharpest outing of the season on Saturday night, limiting the Pittsburgh Pirates to two singles over seven scoreless innings as the Seattle Mariners secured a 1–0 victory at T-Mobile Park. The right-hander struck out a season-high eight without issuing a walk, needing 99 pitches to match his longest appearance of the year. Rookie third baseman Ben Williamson provided the game’s only run in the sixth inning, driving a cutter from reliever Caleb Ferguson into the right-center gap for an RBI double that scored Jorge Polanco. Williamson entered the night with one run batted in since late May. Seattle’s bullpen protected the slim margin, with Matt Brash working a clean eighth inning and Andrés Muñoz recording his 20th save. Pirates starter Mike Burrows allowed three hits and four walks across five shutout innings before yielding to the bullpen. The win improves Castillo to 5–5 and marks his second consecutive scoreless start, spanning 13 innings. The clubs conclude the three-game series on Sunday, when Mariners right-hander George Kirby is slated to face Pirates rookie Paul Skenes.