PHOENIX — Arizona manager Chip Hale couldn't hide his frustration after the Diamondbacks finished a 1-6 homestand that dropped them four games under .500.
"Just poor play on this homestand. It's disappointing after coming off a pretty good series in Cincinnati," Hale said. "For some reason we have not played well, and that's probably on me and the coaches. We need to do a better job of preparing them."
Switch-pitcher Pat Venditte earned his first major league win, aided by Marcus Semien's two-out, two-run single in the 11th for the go-ahead runs. Semien's big hit came after singles by Danny Valencia and Stephen Vogt. Josh Phegley was hit by a pitch from Ziegler (1-1) to load the bases.
Ziegler had to escape a bases-loaded jam in the 10th and took the loss against his former team after allowing three runs and six hits in 1 2-3 innings.
"I made some good pitches and early on they found a lot of holes. It made me have to work a lot harder to just get out of the first (10th) inning," Ziegler said. "Then in the (11th) inning they did a really good job going the other way with pitches. Sometimes that happens."
"This is probably, this year, the hardest we've fought after giving up a deficit late," A's manager Bob Melvin said. "I really didn't want to use him (Venditte). Next thing you know I'm using him two innings and he's getting his first win."
The Diamondbacks forced extra innings on David Peralta's sacrifice fly in the ninth.
Drew Pomeranz threw three inside pitches to Ender Inciarte that backed him off home plate, the third one sparking a heated exchange of words between the two. After Hale came out to calm Inciarte, he ripped a single up the middle that almost hit Pomeranz.
"It's not fun when a guy is throwing at your head. If you can't pitch inside, you shouldn't throw inside," Hale said. "That is unacceptable. Hopefully we will get some new rules where if that ball is around his head he gets thrown out of the game automatically."
Peralta's home run led off the bottom of the third, his 14th of the season, to give the Diamondbacks a 3-2 advantage. The A's drew even on a homer from Stephen Vogt in the fourth.
The Diamondbacks took a 2-0 lead on pair of two-out hits in the second inning, both coming after a throwing error by A's starting pitcher Jesse Chavez. Oakland responded by taking advantage of a Diamondbacks error in the top of the third, also after two outs.
Chavez lasted five innings and allowed three runs on eight hits with six strikeouts and a walk, also collecting his first major league hit in the fifth. But he was thrown out at third base after stumbling around second on a single by Burns.
Allen Webster yielded three runs, one earned, in five innings. Peralta had three hits and two RBIs for Arizona.
Silvino Bracho made his major league debut in the ninth, the 27th pitcher the Diamondbacks have used this season. That's one shy of tying the team record from 2010.
WALKS TO REMEMBER
Arizona All-Star Paul Goldschmidt drew his 99th and 100th walks, a single-season high for Goldschmidt that tied Luis Gonzalez's club record of 100 in 2001.
Athletics: INF Brett Lawrie sat out with back tightness but could return to the lineup Monday, Melvin said.
Diamondbacks: LHP Andrew Chafin was sent down to Triple-A Reno for eight days of rest before he is eligible to return to the majors. Chafin has logged 67 1-3 innings for Arizona in his first full season in the big leagues. ... INF Aaron Hill has a bruised hand but was available.
Athletics: LHP Felix Doubront (1-1, 3.70 ERA) is scheduled to face the Angels on Monday in Oakland.
Diamondbacks: Robbie Ray is coming off a loss to St. Louis last week and seeks his first win since July 7. Ray (3-10, 3.86) faces the Rockies on Monday in Denver.