Madison Bumgarner became the first pitcher in 48 years to hit two grand slams in a season, and Buster Posey also hit a slam Sunday that boosted the San Francisco Giants over the Arizona Diamondbacks 8-4.San Francisco Giants' Madison Bumgarner, right, is congratulated by Brandon Crawford (35) after Bumgarner hit a grand slam off Arizona Diamondbacks' Matt Stites in the sixth inning of a baseball game Sunday, July 13, 2014, in San Francisco.San Francisco Giants' Buster Posey swings on a grand slam off Arizona Diamondbacks' Vidal Nuno in the fifth inning of a baseball game Sunday, July 13, 2014, in San Francisco.San Francisco Giants' Madison Bumgarner watches his grand slam off Arizona Diamondbacks' Matt Stites in the sixth inning of a baseball game Sunday, July 13, 2014, in San Francisco.San Francisco Giants pitcher Madison Bumgarner works against the Arizona Diamondbacks in the first inning of a baseball game Sunday, July 13, 2014, in San Francisco.