Updated

Yonder Alonso went 2-for-4 with a two-run homer and the San Diego Padres held on in the ninth for a 7-6 victory over the Arizona Diamondbacks in the opener of a three-game set at Petco Park.

Trailing by four, Arizona put two runners on to start the ninth and forced the Padres to bring in closer Huston Street. Gerardo Parra clubbed a three-run homer to make it one run game, but Street notched his seventh save when he got Martin Prado to fly out to end the game

Everth Cabrera had a pair of hits and two RBI, while Chris Denorfia knocked in a run and scored twice while finishing 2-for-4. Jason Marquis (3-2) worked around five walks to surrender just three runs on four hits over six frames.

"We're finding the hits, we're being aggressive and swinging at the right pitches," Alonso said. "It just keeps snowballing. We're just trying to get on base for everybody, and have good at-bats so the guy behind us can get it done."

The Diamondbacks dropped their fourth game in a row, registering just five hits before the ninth inning. Miguel Montero went 2-for-3 with a solo homer and three runs scored and Eric Chavez chipped in an RBI double in the setback.

Wade Miley (2-1) was saddled with the loss, charged with four runs on nine hits and three walks over five innings of work. He carried a one-run lead heading into the fifth, but couldn't hold the advantage.

"I felt alright, but I just wasn't executing pitches. I have to look at some video, work on some things and go from there," said Miley.

After putting a runner on, he surrender a two-run blast to Alonso that cleared the right field wall and gave the Padres the lead for good.

Kyle Blanks then plated a run with a single in the seventh and Cabrera's sacrifice squeeze bunt and Headley's ensuing RBI double in the eighth created a four-run cushion for San Diego.

Montero led off the second with a homer to give Arizona the early edge, but the Padres countered with a pair of runs in the bottom half of the frame.

Jedd Gyorko started the inning with a double and three batters later crossed the plate on a single from Denorfia. Cabrera then followed with a triple to push Denorfia home and the Padres held a 2-1 advantage.

The Diamondbacks jumped back in front, 3-2, in the fourth when Cliff Pennington's groundout to second plated a run. Earlier in the inning, Chavez tied the score with a double following walks to Jason Kubel and Montero.

Game Notes

The Padres have won seven of their last nine games ... Marquis improved to 3-7 lifetime against Arizona in 16 meetings ... Gyorko went 3-for-4 with two doubles ... The Diamondbacks were 2-for-8 with runners in scoring position.