Buoyed by Josh Donaldson's first career multi-homer game, the visitors rocked the lefty for six runs in 3 2/3 innings to blow past Houston, 10-1, as the A's extended their dominance over the Astros and tested the home team's patience to open up a four-game set in Minute Maid Park.
Houston is now 4-19 against Oakland since becoming AL West rivals last season, and the A's are off to a 4-0 start against the Astros in 2014.
They did it by rocking Oberholtzer, whose record had not matched his relative success on the mound. Entering the game, he was just 4-8 in his career but had a 2.76 ERA in 14 starts, including four solid efforts this season.
"I wouldn't say [it felt] weird, but I guess it's something new," Oberholtzer said of his struggles. "It's baseball, and I get an opportunity to work at all of it tomorrow. This won't stop me going forward."
Between some sloppy defense behind him and the aggressive A's lineup, Oberholtzer never had much of a chance.
Donaldson ripped a two-run shot off the southpaw in the first, and there was no lull after that. Donaldson scored again in the third on a Derek Norris single that preceded Alberto Callaspo's own two-run dinger, the final dagger for Oberholtzer's evening.
"They did a good job of boxing me in," Oberholtzer said. "I didn't feel much let up from them."
He finished with a whopping 93 pitches on eight hits and two walks through just 11 recorded outs.
"Some nights, you just don't have it," said Astros manager Bo Porter. "I think [Oberholtzer] tried to battle through it. He didn't have that sharp breaking ball and the changeup he's had in the good outings. Once you can't get a feel for those, it turns you into a one-pitch pitcher.
But the Astros' defense was certainly no help. A bobbled ball at shortstop prevented an inning-ending double play in the second, and Coco Crisp's single eventually plated a run. Crisp reached second on George Springer's misfire back into the infield.
Even Matt Dominguez, so renowned for his glove work at the hot corner, committed a pair of errors on one play. The Astros ultimately made five errors in the first five innings, which matched their hit total during those frames.
"We've been playing really well defensively and haven't had games with multiple errors," Porter said. "It's a part of the game. Do you want to make them? No.
"But Matt is one of our better defenders, and I'm not going to put too much weight into him making one poor decision with the baseball after an error."
Meanwhile, the Astros' bats opened hot but ran into a familiar problem: hitting with runners on base. Houston threatened in each of the first two innings but only scored on a first-inning walk and left five runners on during the two frames.
They led off the fourth and fifth innings with hits, but the A's Scott Kazmir retired Houston in order after that each time.
"We had the bases loaded there in the first and ... some opportunities to get a big hit and make a game of it early," Porter said. "[Kazmir] was able to get out of it. When you don't get those hits that can put up two or three runs, it normally comes back to haunt you."
Kazmir lasted six innings, striking out seven and surrendering the lone run. It was more than enough for an Oakland offense that wouldn't quit.
Houston loaded the bases in the ninth inning, but Carlos Corporan's flyout to end the game only ensured that the Astros matched the A's in number of men left on base with 11.
The A's added a pair of runs in the fifth inning off reliever Paul Clemens to effectively seal Houston's eighth loss in its last nine home games since opening the season with a pair of wins over the Yankees. Clemens was ejected in the seventh inning for hitting Jed Lowrie on the backside with a pitch, seemingly continuing the beef from last week in Oakland.
"Surprised, yeah," Clemens said. "It's a tough situation for the umpire, but I respect his decision, follow it and move on."
Clemens denied purposefully plunking Lowrie, saying he "cut" a fastball already aimed for the inside part of the zone.
Donaldson brought Lowrie home with a massive homer to deep left-center field, his second of the game. The third baseman now has three home runs, eight hits -- including three doubles -- six runs and eight RBIs in four games this season against Houston.
"It was neat," Donaldson said of the multi-homer outing. "I [said] yesterday I was going to hit three today. I fell one short. It was nice to have a good game, especially after the last three days."
The Astros and A's still have three games remaining in this weekend's set, giving Houston plenty of chances to reverse its luck against Donaldson and the defending AL West champs.