SAN DIEGO -- To say Erick Aybar was in a slump as he approached the plate in the eighth inning of a scoreless tie at Petco Park Wednesday night is an understatement.

The veteran Padres shortstop was hitless in his previous 16 at-bats and had looked overmatched in his first two at-bats against Arizona's Zack Greinke on Wednesday. And beyond the 0-for-16, Aybar was 1-for-19 and 2-for-34.

"It's been tough, but I work hard every day," said Aybar, who had been out for early batting practice Wednesday afternoon.

The work finally paid off.

Aybar homered off Greinke with one out in the eighth inning to break up a classic, scoreless pitching duel between the Arizona right-hander and Padres right-hander Jhoulys Chacin to give the Padres a 1-0 victory at Petco Park.

Aybar pulled a full-count, 82-mph slider from Greinke 361-feet into the right-field seats.

"Greinke is tough," said Aybar, who is 12-for-33 lifetime against Greinke, although this was his first home run. "He knows how to pitch."

"Not good," said Greinke. "I definitely could have made a better pitch right there. I was trying to throw a borderline strike. I would have been happier with a ball than an inch or two over the plate. It was just not a very good pitch.

"The command was really good, probably the best command I've had. But you make a mistake, it's gonna get hit. Tough loss."

"Zach did exactly what he was supposed to do," said Arizona manager Tony Lovullo. "He gave us eight great innings. You have to tip your hat to their starting pitcher. He did a good job of keeping us off balance."

Chacin and Greinke had battled through 7 1/2 scoreless innings when Aybar connected.

Chacin, who picked up his second win of the season to even his record at 2-2, allowed three hits and a walk with five strikeouts in eight scoreless innings. Arizona had one runner in each of the first four innings before Chacin closed out his night by retiring the final 14 Diamondbacks he faced. No Diamondback reached second against Chacin, who retired eight Diamondbacks on ground balls.

"My sinker was really working," said Chacin, who the Padres signed as a free agent over the winter. "I could throw it for strikes, which was the key to getting deep into the game."

Chacin's two wins have come against the Giants' Madison Bumgarner and Greinke.

"It's definitely more exciting going inning by inning against pitchers like that. And that's all you can do, try to go inning by inning."

Chacin has pitched 14 2/3 innings at Petco Park this season without allowing a run.

Right-hander Brandon Maurer followed Chacin and picked up his second save despite allowing a lead-off single in the ninth to A.J. Pollock. Maurer struck out Diamondbacks cleanup hitter Jake Lamb on a full-count changeup to end the game with the tying run at third.

Greinke had allowed only two hits and a walk with a fourth Padre reaching base on an error through the first 7 1/3 innings before Aybar came to the plate with a .128 average (5-for-39).

The win snapped a five-game losing streak for the Padres. Arizona had won three straight.

"That was a classic between two pitchers with very similar stuff," said Padres manager Andy Green.

NOTES: A night before his game-winning homer, Aybar made his major league pitching debut, coming in from shortstop to get the final out in an 11-2 loss to Arizona. ... The Padres placed RHP Jarred Cosart on the 10-day disabled list with a right hamstring strain suffered during Tuesday night's start. ... RHP Luis Perdomo (right posterior shoulder inflammation) is expected to come off the disabled Sunday and start in Cosart's scheduled spot. ... RHP Kevin Quackenbush was promoted from Triple-A El Paso to immediately take Cosart's roster spot. ... Arizona 3B Jake Lamb equaled his career best by reaching base in a 14th straight game with a fourth-inning single. ... Padres 1B Wil Myers extended his hitting streak to 10 straight games with a single in the bottom of the fourth. ... Paul Goldschmidt was 0-for-4 Wednesday to end of streak of reaching base in 18 straight games against the Padres.