SAN DIEGO (Interstat) — Merrill Kelly pitched seven strong innings, Nolan Arenado homered and the Arizona Diamondbacks defeated the San Diego Padres 3-1 on Thursday night at PETCO Park.

Kelly allowed one run on three hits and struck out six, improving to 7-8 on the season. The veteran right-hander retired the final 11 batters he faced and did not allow a hit after the fourth inning. Paul Sewald earned his 21st save with a perfect ninth inning, striking out two.

The Diamondbacks snapped a two-game losing streak to the Padres, who had taken the first two games of the four-game series by scores of 10-4 and 4-1. Arizona improved to 46-47, level with San Diego’s identical record after the loss.

Arenado’s solo home run in the sixth inning proved decisive, breaking a 1-1 tie. The third baseman connected for his 11th homer of the season, sending a 1-1 pitch from reliever Yuki Matsui to left-center field. It was one of three solo runs Arizona scored, and the only extra-base hit among the team’s eight hits.

The Diamondbacks opened the scoring in the fourth inning. Geraldo Perdomo’s two-out single brought home Tommy Troy, who had singled earlier in the frame. That made it 2-1 and gave Arizona the lead after San Diego’s early advantage.

San Diego struck first in the second inning when Manny Machado hit his 19th home run of the season, a solo shot to right field off Kelly. The Padres managed only three hits in the game, with Machado accounting for two of them, including his home run and a single in the fourth.

Arizona tied the game in the fourth inning on a two-out rally. Max Kepler singled and Lourdes Gurriel Jr. followed with a single to put runners at the corners. Arenado then struck out, but a wild pitch allowed Kepler to score, knotting the game at 1-1.

Kelly worked out of trouble in the fourth after Machado’s single and a walk to Gavin Sheets. Jake Cronenworth grounded into a double play to erase the threat. The Diamondbacks turned two double plays in the game, the other coming in the fifth inning when Luis Campusano walked and Miguel Andujar grounded into a twin killing.

Griffin Canning took the loss for San Diego, falling to 1-7. He allowed two runs on seven hits over 4⅔ innings, striking out five and walking one. Canning was lifted after Perdomo’s run-scoring single in the fifth inning.

The Padres’ bullpen kept the game within reach. Bradgley Rodriguez pitched 1⅓ scoreless innings with two strikeouts, and Adrian Morejon added a scoreless inning with two strikeouts. Wandy Peralta struck out one in a perfect eighth inning. But Matsui, who had not allowed a run in his previous five outings, gave up Arenado’s homer in his lone inning of work.

Arizona added an insurance run in the sixth on Arenado’s homer, and Kelly set down the Padres in order in the fifth, sixth and seventh innings. Kevin Ginkel pitched a scoreless eighth for the Diamondbacks, striking out one.

San Diego’s best chance to rally came in the eighth inning, when pinch-hitter Luis Campusano led off with a flyout to center field. Miguel Andujar grounded out and Sung-Mun Song struck out to end the inning. In the ninth, Sewald struck out Fernando Tatis Jr. and Xander Bogaerts around a flyout by Jackson Merrill to secure the victory.

The attendance was 39,270, and the game lasted 2 hours, 34 minutes.

Arizona’s offense was limited but timely. Perdomo had two hits and an RBI, while Gurriel, Gabriel Moreno, Kepler, Troy and Ketel Marte each had one hit. The Diamondbacks left six runners on base and struck out nine times.

San Diego’s lineup managed only three hits against Kelly and two relievers. Machado’s two hits led the Padres, who also had a single from Tatis Jr. in the third inning. Tatis was then picked off first base by catcher Moreno after a successful challenge by Arizona overturned the original safe call.

The Padres grounded into two double plays, and their three hits matched a season low. They struck out 12 times as a team.

The series continues with the Diamondbacks heading to Los Angeles to face the Dodgers starting Friday, while San Diego opens a three-game homestand against the Toronto Blue Jays.

Interstat’s game simulator projected a final score of Arizona Diamondbacks 4, San Diego Padres 1. Interstat’s ELO system gave the Padres a 56.30 percent probability to win. San Diego was installed as a pregame favorite with a spread of minus 1.5 runs. The combined total of four runs went over the over-under line of 8.5.