PHOENIX (Interstat) — Trevor McDonald pitched six shutout innings and the San Francisco Giants broke open a scoreless game with three-run outbursts in the fifth and sixth innings Wednesday night, holding off the Arizona Diamondbacks 6-4 at Chase Field.

The Giants, who entered having lost the first two games of the series and eight of their previous 10, snapped a three-game losing streak and improved to 36-50. The Diamondbacks fell to 43-43, failing to climb above .500 for the first time since June 24.

McDonald allowed four hits, walked one and struck out three over six innings to earn his third win against six losses. The right-hander retired 13 of the final 14 batters he faced after a leadoff single in the fourth by Ketel Marte.

Caleb Kilian recorded the final three outs for his seventh save, working around a one-out walk in the ninth.

Zac Gallen took the loss for Arizona, falling to 3-8. The right-hander allowed six runs on 11 hits over 5 2/3 innings, striking out six and walking one.

The game was scoreless through four innings as both starting pitchers worked efficiently. Gallen allowed only two hits through the first four frames, while McDonald faced just one batter over the minimum through four.

San Francisco broke through in the fifth. Heliot Ramos led off with a solo home run, his sixth of the season, to center field. Jung Hoo Lee followed with a single and Victor Bericato hit a two-run homer to left-center, his fourth, to make it 3-0. Drew Cavanaugh singled but was erased on a forceout, and a double play ended the inning.

The Giants added three more in the sixth. After two strikeouts, Rafael Devers walked. Ramos then tripled to center field, with the ball deflected by right fielder Corbin Carroll, scoring Devers for a 4-0 lead. Lee singled to right, scoring Ramos, and Bericato singled to put runners at the corners. Cavanaugh singled to center, scoring Lee for a 6-0 advantage.

Arizona mounted a comeback in the eighth. Nolan Arenado led off with a single off Randy Rodriguez, who had relieved McDonald after six. Pavin Smith followed with an RBI single. Tommy Troy then singled to short, and a throwing error by shortstop Christian Koss allowed both runners to advance. Ketel Marte doubled to left-center, driving in Smith and Troy, and a second throwing error by Koss on the same play allowed Marte to reach third. Marte scored on a groundout by Carroll, cutting the deficit to 6-4. Gabriel Moreno singled but was thrown out trying to advance, and Lourdes Gurriel Jr. struck out to end the inning.

Arizona had the tying run at the plate in the eighth but could not get closer. In the ninth, Kilian struck out Adrian Del Castillo and Arenado looking, then got Smith to ground out to first.

Marte led the Diamondbacks with two hits and an RBI. Troy, Moreno, Arenado and Geraldo Perdomo each had one hit. Carroll drove in a run but went hitless in four at-bats.

For San Francisco, Ramos had a home run, a triple and three RBIs. Lee and Bericato each had two hits, with Bericato driving in two. Cavanaugh added two hits.

The game drew 17,142 fans and lasted 2 hours, 52 minutes.

The Diamondbacks had won the previous two games of the series, including an 8-2 victory on Tuesday and a 5-4 win on Monday. Arizona had taken six of the previous seven meetings between the clubs dating to May 18.

San Francisco heads to Colorado for a three-game series beginning Friday. Arizona returns home to host Milwaukee for a three-game set starting Friday.

Interstat’s game simulator projected a final score of San Francisco 5, Arizona 4. Interstat’s ELO system gave the Diamondbacks a 55.00 percent probability to win. San Francisco was installed as a pregame favorite with a spread of minus 1.5. The total score of 10 went under the over-under line of 9.5.