The Braves won three of four in the series to cap San Francisco's 1-7 road trip.
Adams' homer was the first of his career.
Brandon Phillips led off the big inning with a homer off Cain (3-7), the first of six straight hits. The Braves finished with nine hits in the inning.
The Braves and Giants combined for seven homers, including four by Atlanta, and 31 hits. Nick Markakis hit a two-run homer in the first. Matt Adams hit his third homer of the series, and 13th of the season, in the fourth.
Rookie Jason Hursh (1-0) got his first major league win. Braves closer Jim Johnson gave up two runs in the ninth but got his 14th save.
