SAN DIEGO -- Until Saturday night, June had been a tough month for San Diego Padres right-hander Andrew Cashner.

In his first five starts this month, Cashner was 0-2 with a 8.31 ERA and allowed 35 hits and 14 walks in 26 innings.

But his fortunes reversed at Petco Park when Cashner allowed two runs, eight hits and no walks in seven innings to lead the Padres to a 7-2 victory over the Arizona Diamondbacks.

"Everything I've been working on was better tonight," said Cashner, who picked up only his third win against nine losses this season and only his second win since April 19.

"My sinker was back, my change was there ... this was something to build off of."

Padres manager Pat Murphy said, "He showed mental toughness tonight. If he stays on this course, he can be something special."

And for one of the few times in almost two years, Cashner had plenty of support both offensively and defensively.

The seven runs were the most scored by the Padres while Cashner was on the mound since Sept. 10, 2013. And Cashner, who had been tagged for 17 unearned runs in 16 starts this season, was the beneficiary of several excellent defensive plays.

The biggest blow was a two-run homer by left fielder Justin Upton in the fifth inning that snapped a 2-2 tie and allowed the Padres to move past the Diamondbacks into third in the National League West. The Padres go for a sweep of the three-game series on Sunday afternoon.

Cashner (3-9), who also drove in his first run this season with a single on a safety squeeze bunt, had six strikeouts.

Third baseman Yangervis Solarte had three hits and an RBI for the Padres.

Five other players -- Upton, right fielder Matt Kemp, first baseman Yonder Alonso, center fielder Will Venable and shortstop Clint Barmes -- had two hits in the 15-hit attack. Kemp, Alonso and catcher Derek Norris also drove in runs for the Padres.

Upton's 14th homer of the season -- but only his second in his last 32 games -- came on a full-count pitch from Arizona starter Jeremy Hellickson (5-5) and broke a 2-2 tie.

Alonso set up Upton's 360-foot, opposite-field drive with a two-out double to left. Upton's homer bounced on top of the wall in right.

"The two-run homer by Justin really hurt us," Arizona manager Chip Hale said. "You have certain guys on teams you try to make sure don't beat you and he's the guy on this club. It's just disappointing he was able to get that ball on the outer half and hit it out to right."

The Padres took a quick lead with two runs in the first against Hellickson.

Kemp, making his fourth start as the Padres' leadoff hitter, opened the game with a double, moved to third on Solarte's groundout to second and scored on Alonso's single.

Upton followed with a single to right, sending Alonso to third. Alonso scored on Norris' groundout to Diamondbacks shortstop Nick Ahmed, who had to charge the hopper, eliminating any shot at an inning-ending double play.

But after working out of a jam in the second -- the Diamondbacks didn't score after loading the bases on three singles with one out -- Cashner gave up two runs in the third on consecutive two-out doubles by first baseman Paul Goldschmidt, left fielder David Peralta and right fielder Yasmany Tomas.

An inning after Upton's home run, the Padres extended their lead to 7-2 with three runs on five singles.

Venable and Barmes opened the sixth with singles, putting runners at the corners with none out. After second baseman Alexi Amarista popped out to short left, Cashner placed a perfect squeeze bunt up the third-base line with Venable sliding home ahead of the throw from third baseman Jake Lamb to make it 5-2.

Kemp followed with a single to left off right-handed reliever Randall Delgado that scored Barmes. Cashner then scored on a single by Solarte.

Meanwhile, Cashner retired nine of the next 10 Diamondbacks he faced after Tomas' double in the third.

"If Cashner executes pitches with that stuff, we have a good chance to win," Murphy said.

NOTES: Padres 2B Cory Spangenberg departed Saturday's game in the fourth inning with a sprained left knee. He suffered the injury while making the pivot on a first-inning double play when he was slid into by Arizona shortstop Nick Ahmed. ... Padres RHP Josh Johnson will soon resume a throwing program after an MRI taken earlier this week on his reconstructed right elbow was inconclusive, although Padres manager Pat Murphy said "they don't know about the integrity of the ligament." ... Ahmed batted leadoff for the second time this season Saturday. ... Saturday night was the first time this season the Padres scored more than five runs for Cashner.