PHOENIX (Interstat) — The Arizona Diamondbacks used a three-run first inning and another three-run third to defeat the San Francisco Giants 8-2 on Tuesday night at Chase Field, extending their winning streak over the Giants to five games.

Brandon Pfaadt pitched 5 1/3 innings of three-hit ball, allowing one earned run with two strikeouts to earn his first win of the season after a 1-1 record. Landen Roupp took the loss, dropping to 5-8, as he allowed six runs on five hits over 2 2/3 innings.

The game began with a promising sign for San Francisco when Luis Arraez led off the top of the first inning with a single to center field. But the Giants could not capitalize, as Bryce Eldridge, Casey Schmitt and Rafael Devers all made outs to leave Arraez stranded.

Arizona seized control in the bottom of the first. Ketel Marte grounded out to begin the inning, but Geraldo Perdomo drew a walk. Corbin Carroll struck out swinging, then Gabriel Moreno walked to put two runners on. Lourdes Gurriel Jr. stepped in and launched a three-run home run to left-center field, his second of the season, scoring Perdomo and Moreno to give the Diamondbacks a 3-0 lead. Max Kepler followed with a double, but Nolan Arenado struck out to end the inning.

The Giants went down in order in the top of the second, with Jung Hoo Lee grounding out, Heliot Ramos flying out and Matt Chapman grounding out. Arizona added to its lead in the bottom of the third. After a leadoff walk to Gabriel Moreno — the call was overturned on challenge — Gurriel popped out. Kepler singled to center, moving Moreno to second, and Arenado singled to left to load the bases. Pavin Smith struck out after a challenge confirmed the call, but Jorge Barrosa drew a walk to force in Moreno, making it 4-0. Ketel Marte then singled to left, scoring Kepler and Arenado, pushing the lead to 6-0. Geraldo Perdomo lined out to Arraez to end the inning.

San Francisco’s best chance to get back into the game came in the top of the third. After Drew Gilbert struck out and Drew Cavanaugh popped out, Arraez tripled to right field, his seventh triple of the season. But Eldridge popped out to shortstop, leaving Arraez stranded. The Giants managed only a walk to Devers in the fourth, then grounded into a double play.

Arizona’s offense continued to produce in the sixth. After a popout and a groundout, Ketel Marte crushed a solo home run to right, his 17th, to extend the lead to 7-0. The Giants finally got on the board in the top of the sixth. With one out, Arraez hit a solo home run to right, his fourth of the season, cutting the deficit to 7-1. But Bryce Eldridge and Casey Schmitt both flew out to center to end the inning.

San Francisco added another run in the seventh when Rafael Devers led off with a solo home run to left-center, his 15th, making it 7-2. Jung Hoo Lee grounded out, Heliot Ramos grounded out and Matt Chapman popped out to first to end the inning.

Arizona responded in the bottom of the eighth. Jorge Barrosa led off with a soft bunt single off pitcher Adrian Houser. Ketel Marte grounded out, advancing Barrosa to second. Geraldo Perdomo flew out to center, but Corbin Carroll walked. Gabriel Moreno singled to center, scoring Barrosa to make it 8-2. Gurriel popped out to end the inning.

The Giants went down in order in the ninth, with Eldridge striking out, Schmitt lining out and Devers walking before Jung Hoo Lee flew out to left.

For Arizona, the bullpen held San Francisco scoreless over the final three innings. Juan Morillo pitched a perfect seventh with no hits and no strikeouts. Drey Jameson struck out one in a scoreless eighth, and Taylor Clarke allowed one earned run on one hit in the ninth. Ryan Thompson pitched two-thirds of an inning without allowing a hit.

For San Francisco, Adrian Houser threw 5 1/3 innings of relief, allowing five hits and two earned runs with one strikeout. The Giants’ pitchers combined for two strikeouts, 40 balls and two balls in play; the Diamondbacks’ pitchers combined for eight strikeouts, 64 balls and eight balls in play.

Luis Arraez led San Francisco’s offense with three hits in four at-bats, including a triple and a solo home run, and drove in one run. Rafael Devers went 1-for-2 with a walk and a solo homer. The Giants managed only four hits total.

For Arizona, Lourdes Gurriel Jr. went 2-for-5 with a home run, a double and three RBIs. Ketel Marte also had two hits, including a home run, and drove in three runs. Gabriel Moreno had two hits and two walks, scoring twice. Arizona collected 10 hits.

The attendance was 20,420, and the game lasted 2 hours, 30 minutes.

With the victory, Arizona improved to 43-42, while San Francisco fell to 35-50. The Diamondbacks have now won five consecutive matchups against the Giants dating to May 26, including Monday’s 5-4 victory in the opener of this series. The teams will meet again Wednesday for the finale of the three-game set.

San Francisco’s recent struggles continue. The Giants had lost two of three to before taking two of three from Atlanta last weekend, but they have now dropped the first two games of this road trip. Arizona, meanwhile, has won three of its last four after a difficult stretch that included losses at Tampa Bay.

The next 10 games for San Francisco include the series finale at Arizona on Wednesday, then a three-game road series at Colorado, followed by a homestand against Toronto and Colorado. Arizona will host San Francisco again Wednesday, then welcome Milwaukee for three games before a four-game road trip to San Diego and a three-game series at Los Angeles.

Interstat’s game simulator had projected a final score of San Francisco 5, Arizona 4. Interstat’s ELO system gave Arizona a 54.40 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.