Bumgarner (9-5) won for the fifth time in six starts, limiting the Dodgers to three hits and no walks. The left-hander struck out nine while giving up two earned runs in the 113-pitch performance.
At the plate, Bumgarner drew a bases-loaded walk in the second inning, triggering a three-run Giants outburst enabled by second baseman Nick Punto's error, and added a sacrifice fly in the fourth for a 4-0 lead.
The Dodgers' Stephen Fife (3-3) was the loser, surrendering four runs (only one earned) on seven hits over 4 1/3 frames.
Tim Federowicz belted a two-run homer for Los Angeles.