Khris Davis crushed a two-run homer off Blake Parker to trim the Angels' lead to 10-8 in the eighth, prompting manager Mike Scioscia to bring in closer Bud Norris to attempt a four-out save. But Norris couldn't stop the bleeding, yielding an RBI single to Pinder and a two-run single Bruce Maxwell, allowing the A's to surge ahead, 11-10.
"Great, great at-bats throughout the game," A's manager Bob Melvin said. "It's hot out there, you're down big and there's just no quit. They like to play. You persevere, you battle through and give yourself a chance at the end and come up with some really good at-bats. That was a really good team win."
Santiago Casilla survived a bases-loaded jam in the eighth and Blake Treinen pitched a scoreless ninth to seal the A's second straight win over the Angels. Mark Canha, Pinder and Davis homered for Oakland, which outhit the Halos, 18-12, en route to a season-high in runs. Pinder finished the afternoon with a career-high four hits and fell a triple shy of the cycle.
"It's one that those guys snatched from us," Angels manager Mike Scioscia said.
Yunel Escobar and Mike Trout homered for the Angels, while Kole Calhoun, C.J. Cron and Juan Graterol delivered multi-hit efforts. Trout, who launched his 22nd home run of the season in the fourth, is one hit away from 1,000 for his career.
The loss dropped the Angels (55-57) two games below .500 and put them three games behind the Royals for the second American League Wild Card spot.
Neither club received much length from its starter. Angels right-hander Ricky Nolasco surrendered five runs over four-plus innings, while A's left-hander Sean Manaea couldn't get out of the fourth and departed after allowing six runs (five earned).
"I think he's just hit a rough patch," Melvin said about Manaea. "You can get a little tired. The [velocity] is not as high as it's been all year, he feels fine. The innings are starting to mount. It's just a tough patch for him."
MOMENTS THAT MATTERED A's rally in the eighth: Pinder's solo home run cut the Angels' lead to 10-6 in the seventh, and the A's continued to chip away at the deficit in the next inning. Parker retired the first two batters he faced, but then unraveled, surrendering a single to Jed Lowrie, followed by an opposite-field shot to Davis. Ryon Healy kept the rally alive with a double, precipitating Parker's exit.
"Just wanted to challenge him, up four runs," said Parker, who saw his streak of 27 consecutive outings without allowing an earned run at Angel Stadium come to an end. "He put good wood on it, ball carried out. If I had to do it over again, I'd probably make the same pitch. I just want to attack guys and stay aggressive."
Casilla escapes jam: The Angels came back to threaten in the bottom of the eighth, as Cron lined a double off Casilla, putting the potential tying run on second with one out. Casilla then hit Andrelton Simmons on the ribs and issued a two-out walk to Ben Revere to load the bases. Scioscia opted to have Luis Valbuena pinch-hit for Graterol, but Casilla struck out Valbuena swinging to end the inning, preserving the A's slim lead.
"We've seen Casilla bring it down to the wire before," Melvin said. "But he made a pitch when [he] had to and that gives you a little bit more momentum, too, when you know you get out of a jam, when even a bloop can cost you at that point."
QUOTABLE "It felt like I was sitting in an oven at Thanksgiving all day. It could have been worse, it could have been like 12 degrees and freezing." -- Maxwell, on the long game
SOUND SMART WITH YOUR FRIENDS Sunday's series finale between the Angels and A's lasted four hours, 12 minutes, making it the longest nine-inning game in Angel Stadium history.
WHAT'S NEXT Athletics: The A's get a day off before they head back home for a two-game series beginning Tuesday against division foe Seattle. Righty Kendall Graveman will make his second start since being activated off the disabled list. First pitch is slated for 7:05 p.m. PT.
Angels: The Angels continue their nine-game homestand on Monday, hosting the Orioles for the first of three games at Angel Stadium. Right-hander JC Ramirez (10-9, 4.03 ERA) will take the mound in the opener. First pitch is scheduled for 7:07 p.m. PT.