Boston Red Sox at St. Louis Cardinals: Final Score & Recap

The Boston Red Sox handed the St. Louis Cardinals a 9-3 defeat at Busch Stadium on April 12, 2026, handing the home side a loss that the DiamondIQ model's estimate of pre-game win probability had not foreseen, as St. Louis entered with a 54 percent chance to win and finished at zero. Boston struck early with two runs in the first inning and added another in the second before delivering the knockout blow in the fourth, when the Red Sox pushed across four more runs to take a commanding lead they never relinquished. St. Louis managed just three runs, coming in scattered fashion in the second, sixth, and eighth innings, and committed one error against a Boston club that played clean defense throughout.

The decisive sequence arrived in the fourth inning, when Jarren Duran's double off Andre Pallante shifted win probability by plus 12.9 percent in Boston's favor, the single largest swing of the game. That blow was part of the four-run outburst that effectively ended any realistic Cardinals comeback. Earlier in the second inning, Jordan Walker had provided St. Louis its only moment of genuine optimism with a home run off Brayan Bello that moved the Cardinals' win probability by plus 6.7 percent, but a pair of groundouts in that same inning — José Fermín's at minus 6.8 percent and Alec Burleson's at minus 6.0 percent — illustrated how consistently St. Louis failed to capitalize when opportunities arose.

Brayan Bello was the most impactful individual performer of the night by a substantial margin, finishing with a plus 19.8 percent WPA that reflected his ability to limit damage despite allowing Walker's home run. Among position players, Duran led Boston with plus 11.1 percent WPA and a RE24 of plus 1.3, while Caleb Durbin contributed plus 9.5 percent WPA despite a neutral run-expectancy figure, suggesting his value came from sequencing within high-leverage moments. Walker's plus 8.0 percent WPA and plus 1.3 RE24 stood as the lone bright spot in the Cardinals' line, as the DiamondIQ model's estimate ultimately reflected a Boston club that controlled this game from the opening inning.