With Oliver Perez (2-2) pitching for the Mariners, Nate Schierholtz bunted for a single to lead off. Soriano then connected on a 1-2 pitch that sailed over the center field wall.
Carlos Villanueva (2-4) earned the win after pitching flawlessly in the 10th while Blake Parker threw a 1-2-3 11th to pick up his first career save.
Soriano had three RBI while Starlin Castro had a home run for the Cubs, who have won three of their last four games.
Justin Smoak hit a solo shot while Dustin Ackley and Endy Chavez drove one run apiece for the Mariners, who have lost six of nine.
06/29 23:05:32 ET