Chicago Cubs at Seattle Mariners: Final Score & Recap

The Seattle Mariners walked off with a 5-4 victory over the Chicago Cubs on August 22, 2026, at T-Mobile Park, completing a dramatic comeback that swung the DiamondIQ model's estimate from a 45 percent pre-game home win probability all the way to 100 percent by the final out. The Cubs had built what looked like a decisive advantage in the top of the sixth inning, with Michael Busch and Alex Bregman hitting back-to-back home runs off Kade Anderson — contributing +14.6 and +13.8 percent win probability swings respectively — and Tyrone Taylor adding a two-bagger off Carlos Vargas worth another +10.6 percent, turning the inning into a three-run rally. A Seiya Suzuki double play in that same frame cost the Cubs 14.3 percent in win probability and proved to be a missed opportunity to extend the damage further. Seattle had answered Chicago's first run in the fifth with one of their own, keeping it close enough for what came next.

With the Cubs holding a 4-2 lead entering the bottom of the ninth and Jacob Webb on the mound, Randy Arozarena delivered the single most consequential swing of the game, launching a walk-off home run that registered a staggering +90.2 percent win probability added and finished as the defining moment of the contest. Arozarena ended the night as the game's top performer by a wide margin, posting a cumulative WPA of +94.1 percent and a RE24 of +3.3. Leo Rivas contributed +16.0 percent WPA and +1.7 RE24, while Taylor rounded out the top offensive contributors at +14.5 percent WPA. On the pitching side, Trent Thornton led Seattle's staff with +14.3 percent WPA, followed by Ryan Rolison at +7.8 percent and David Peterson at +3.5 percent, as the Mariners cobbled together enough innings to keep the Cubs at bay until Arozarena ended it in the most emphatic fashion possible.