Boston Red Sox at Seattle Mariners: Final Score & Recap

The Seattle Mariners defeated the Boston Red Sox 3-1 at T-Mobile Park on June 21, 2026, finishing a game the DiamondIQ model had projected as a 63 percent home-team advantage before first pitch and ultimately resolved to 100 percent certainty in Seattle's favor. The Mariners scored in the second, fifth, and sixth innings, while Boston's only run came on a Nate Eaton home run off Logan Gilbert in the top of the third, a swing that briefly shifted Boston's win probability by plus-10.6 percent and represented the Red Sox's lone moment of genuine leverage in the contest.

The decisive stretch came in the bottom of the fifth, when Cole Young singled off Payton Tolle for a plus-13.1 percent win-probability swing, extending the Seattle lead and effectively putting the game beyond Boston's reach. The Red Sox repeatedly squandered opportunities to mount a response, most notably when Rob Refsnyder grounded into a double play in the top of the fourth against Tolle, a minus-10.1 percent shift in win probability, and when Ceddanne Rafaela hit into a double play in the top of the sixth off Logan Gilbert for minus-9.7 percent. Marcelo Mayer's strikeout against Gilbert in the fifth, costing Boston another 9.5 percent in win probability, further illustrated how thoroughly the Mariners' staff suffocated the Boston lineup.

Logan Gilbert led all pitchers with a plus-11.8 percent WPA contribution, navigating Boston's sporadic threats efficiently throughout his outing. Eduard Bazardo and Gabe Speier added plus-8.1 and plus-7.8 percent respectively out of the Seattle bullpen to close it out. Among position players, Mickey Gasper paced all batters with a plus-14.8 percent WPA and a 0.7 RE24, while Eaton's home run gave him a plus-13.6 percent WPA and a team-best 1.2 RE24. Seattle's final line of three runs on six hits with one error was sufficient against a Boston offense that managed just five hits and could not convert when it mattered.