Chris Heston pitched six effective innings in a combined five-hitter for his first big league win, Casey McGehee hit a two-run homer and the San Francisco Giants beat the Arizona Diamondbacks 5-2 Wednesday night Heston (1-0) had a wild pitch and a throwing error that led to Arizona's runs, but shook off both to win in his second big league start. Nori Aoki had three of San Francisco's 14 hits, including a run-scoring double off Jeremy Hellickson (0-1) in the right-hander's Arizona debut. Matt Duffy also had a run-scoring double and Brandon Crawford added a run-scoring single for the defending World Series champions. Arizona went 0 for 8 with runners in scoring position, needing miscues by the Giants to score its two runs.