SAN DIEGO -- Jason Kubel and the Arizona Diamondbacks made spacious Petco Park look like a hitter's park.

Kubel hit two of Arizona's four home runs to help the Diamondbacks beat San Diego 8-5 Saturday night, snapping a seven-game losing streak against the Padres.

Aaron Hill and Justin Upton had solo homers as Arizona finished with 15 hits. Upton's home run went an estimated 443 feet to dead center field.

"It's still a big park," Upton said. "We just got into a few balls and they carried."

Upton had a season-high four hits and Jake Elmore added two RBIs as the Diamondbacks closed to 5 1/2 games behind St. Louis for the second NL wild-card berth.

"It's nice to finally beat these guys," Kubel said. "It seems like a really long time. We really need wins, as many as we can get, and this is a start."

Kubel hit a two-run homer in the first inning. Hill led off the third with his 22nd homer before Kubel followed two pitches later for his career-high 29th home run.

"We came out swinging the bats, everybody really," Kubel said. "We scored early and kept it going."

Upton connected off Miles Mikolas in the fifth inning on a line drive that gave the Diamondbacks a 7-4 lead.

"To be honest with you, I was trying to hit the ball back up the middle and he left the ball up," said Upton. "I won't say it was a no-doubter over the fence, but I knew it was going to carry to at least the fence."

Rookie Wade Miley (15-9) won despite giving up five runs and eight hits in 5 1/3 innings. The left-hander struck out six and had three walks to snap his streak of 24 consecutive starts without issuing more than two walks.

"I got frustrated early and stayed frustrated," Miley said. "I threw pitches in middle of the plate and they made me pay."

Said Upton: "He's been good for us all year, and it was our turn to return the favor. It was nice."

J.J. Putz struck out the side in the ninth for his 29th save in 34 chances.

San Diego had outscored the Diamondbacks 48-25 during the seven-game win streak.

The Padres, who came in having won 13 of 17 games, lost at home for just the sixth time in 23 games.

"When we made a mistake, they had a pretty good swing at it," San Diego manager Bud Black said. "Even when we made some pitches, they had some good swings."

Kubel broke out of a recent slump with his fourth multi-homer game this season. He was batting just .140 (6 for 43) in his last 14 games.

"Lately, it's been coming around and I have been hitting balls harder," Kubel said. "It's starting to feel better, more consistent. Just hoping to keep the feeling going."

Both of Kubel's homers and Hill's home run came off rookie Casey Kelly (1-1), who only lasted into the third inning in his third major-league start.

Kelly, a prized prospect acquired by the Padres from Boston in the Adrian Gonzalez trade, was hit hard for the second straight start. The righty allowed six runs and eight hits in 2 1/3 innings.

"Obviously today, you never want it to happen," Kelly said. "But at the same time, I'm going to learn a lot from this. It's just going to make me better down the road."

After Kubel hit a two-run homer in the first, Jesus Guzman got San Diego even with a two-run double in the bottom of the inning.

Logan Forsythe hit a two-run homer for San Diego in the fourth to cut Arizona's lead to 6-4.

Game notes
Kubel has 10 multi-homer games in his career. ... Miley has given up more than three earned runs only six times in 25 starts. ... San Diego LF Carlos Quentin missed his second straight game and third this week with right knee irritation. ... Padres starting pitcher Clayton Richard was back with the team after his wife, Ashley, gave birth to a son. .. The series concludes Sunday with a pair of rookies throwing -- Arizona LHP Patrick Corbin (5-6, 4.13 ERA) and San Diego LHP Andrew Werner (1-1, 3.00).