PHOENIX — 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. Santiago Casilla worked around a single in the ninth for his second save.
Arizona went 0 for 8 with runners in scoring position, needing miscues by the Giants to score its two runs.
The Giants slid Heston into the rotation after right-hander Matt Cain went on the disabled list with a strained flexor tendon in his throwing arm.
The Diamondbacks scored a run off Heston without a hit in the first inning, when leadoff hitter A.J. Pollock was hit by a pitch, reached third on a throwing error by Heston on a pickoff move and scored on Chris Owings' groundout.
Arizona tacked on another run in the sixth inning after Goldschmidt doubled, advanced to third on a wild pitch and scored on catcher Hector Sanchez's passed ball.
Heston, who made three appearances in the majors last season, allowed two unearned runs on three hits and struck out five.
Hellickson arrived in Arizona in an offseason trade with Tampa Bay, hoping to bounce back from a difficult 2014 season in which he started on the disabled list and went 1-5 with a 4.52 ERA.
Hellickson, who turned 28 on Wednesday, was in trouble from the start against the Giants, though escaped a one-out, bases-loaded jam in the first inning.
San Francisco scored two runs off him in the second inning on consecutive run-scoring doubles by Aoki and Duffy. The Giants kept hitting balls hard and chased him with one out in the fifth inning on a run-scoring single by Crawford that put them up 3-1.
Hellickson allowed three runs on nine hits.
Giants: RHP Tim Hudson will make the first start in the final season of his 17-year career at San Diego on Thursday. The 39-year-old had surgery to remove bone spurs from his right ankle during the offseason, but had a decent spring, going 1-1 with a 3.32 ERA.
Diamondbacks: Arizona has a day off before RHP Chase Anderson makes his 2015 debut against the Los Angeles Dodgers on Friday.
Giants: 1B Brandon Belt was held out of the lineup after straining his groin Tuesday night, but is not expected to go on the DL. He was able to take a few swings in a batting cage on Wednesday and (manager Bruce) Bochy said he should be available this week. … RHP Jake Peavy's stiff lower back loosened overnight and is still on schedule to start Sunday against San Diego.
Diamondbacks: LHP Patrick Corbin, who underwent Tommy John last season, is expected to go on rehab assignment in May and possibly return by early June.