Tanner Bibee struck out a career-high 12 in six innings, Josh Naylor homered twice and had four RBIs, and the Cleveland Guardians beat the Seattle Mariners 8-0 in a battle of American League division leaders. Bibee struck out multiple batters in each of the first five innings, allowing three hits and one walk to improve to 5-2. The right-hander had 11 strikeouts in his previous start on June 12 at Cincinnati, his first double-digit game in the majors. Steven Kwan hit a two-run homer and José Ramírez and Bo Naylor each had two hits for the Guardians. Bryan Woo take the loss.