PHOENIX—Wade Miley shook off a shaky first inning to give his team a chance.

Had his teammates given him even a little bit of support, the left-hander would have kept his undefeated home streak alive.

Miley pitched seven effective innings after his rough start, but Arizona's offense stagnated against Robbie Erlin and San Diego's bullpen in a 5-1 loss to the Padres on Wednesday night.

"We had some opportunities, but were unable to get the big hit, extra-base hit when we needed it," Diamondbacks manager Kirk Gibson said.

The Padres certainly did. Particularly Will Venable.

He's has been on a tear since August started, putting together a 15-game hitting streak and a current run of eight straight games.

Against the Diamondbacks, he hit a run-scoring single off Miley (9-9) in the first inning and later scored on Jesus Guzman's run-scoring single. With the game still close in the eighth, Venable helped give the padding San Diego needed, lifting a two-run homer off Heath Bell to become the first Padres outfielder to hit 20 homers in a season since Mike Cameron in 2007.

"Will's doing a good job of capitalizing on the high breaking ball, the mistake breaking ball, he's not missing it," Padres manager Bud Black said.

Guzman also hit a solo homer and Erlin (2-2) was sharp in his return to the majors, holding Arizona to a run and six hits.

Miley was effective after his early troubles, but the Diamondbacks gave him little support, stranding 10 runners while going 1-for 8 with runners in scoring position.

Willie Bloomquist had three hits, drove in a run and made some tough plays at shortstop in his first game off the disabled list for Arizona, which had its five-game home winning streak end.

"Erlin threw the ball pretty well tonight," said Miley, who lost for the first time in seven home starts. "He kept us off balance and had his stuff working."

The series finale was relatively quiet after Tuesday's wild game of lead changes, hits (26) and lineup shuffling, including a major league-record five different third basemen used by the Padres.

Erlin had a lot to do with it after being called up to take the rotation spot of Edinson Volquez, who was designated for assignment on Saturday.

The young left-hander got himself into a little trouble in the sixth, when he walked Eric Chavez with two outs and gave up a single to Aaron Hill. Bloomquist, who had been out since being hit on the left hand by a pitch on July 26, followed with a single to right to cut San Diego's lead to 2-1

Erlin escaped more trouble in the inning to win for the first time since beating Toronto on July 1.

"I really just try to keep it simple, throw strikes," Erlin said. "It just comes down to executing. Executing gets outs."

Miley has been good since the start of July, going 5-1 with a 2.26 ERA in 10 starts. He wasn't particularly fortunate over his previous three starts, earning three straight no-decisions despite allowing seven earned runs in 21 innings.

Miley's tough luck continued.

He struggled early against the Padres, giving up a leadoff single to Chris Denorfia, a run-scoring double to Venable and a run-scoring single to Guzman to fall behind 2-0 in the first inning.

The left-hander worked through three baserunners in the second inning before settling into a rhythm. He allowed two runs on seven hits and walked five in seven innings.

"I thought I made some pretty good pitches in the first inning," Miley said. "They did a pretty good job of putting some balls in play and hitting the ball hard. That's the way it goes."

NOTES: Diamondbacks 1B Paul Goldschmidt was given the night off after 47 straight starts. ... Arizona RHP Will Harris, outfielder/baserunning coordinator Joel Youngblood and Padres OF Carlos Quentin all shared a birthday on Wednesday. Quentin, on the DL since Aug. 10, will have surgery on his right knee and is done for the season. ... Arizona has Thursday off before opening a three-game series at San Francisco. RHP Randall Delgado, who will start the opener, is 3-1 with a 3.83 ERA his last seven starts.