Giants 5, Cubs 3: Buster Posey went 4-for-4 with a solo homer and Pablo Sandoval collected three hits and two RBIs as visiting San Francisco posted its fourth win in five games after dropping the completion of a suspended contest earlier Thursday.

Posey scored twice and Michael Morse drove in a run for the Giants, who moved one game ahead of Atlanta for the second National League wild-card spot and are 3 1/2 behind the first-place Los Angeles Dodgers in the NL West. Madison Bumgarner (14-9) registered a season-high 12 strikeouts and added an RBI while allowing three runs and seven hits over seven innings and three relievers combined to get the final six outs, with Santiago Casilla working the ninth for his 11th save.

Justin Ruggiano and Welington Castillo hit back-to-back homers and finished with two hits apiece for the Cubs, who lost for the fifth time in eight contests. Travis Wood (7-11) yielded four runs and eight hits in six frames as his winless streak reached 12 starts.

San Francisco grabbed an early lead as Sandoval delivered an RBI single in the first, but Chicago responded in the bottom of the frame as Ruggiano belted a two-out, two-run homer and Castillo followed with his 10th shot of the season. Sandoval plated a run in the third with a double and Bumgarner helped his own cause with a run-scoring single an inning later to forge a 3-3 tie.

Posey led off the fifth with his 14th homer, depositing a 1-0 pitch from Wood over the left-center field wall to put the Giants ahead. Morse added insurance in the seventh with a sacrifice fly and Bumgarner escaped a jam in the bottom half by striking out Javier Baez with runners on second and third and two outs.

GAME NOTEBOOK: Bumgarner fell one strikeout shy of his career high set Sept. 5, 2011 in San Diego. ... Posey finished a triple short of the cycle. ... Baez was Bumgarner's favorite victim, striking out in all four at-bats against the left-hander.