OAKLAND, Calif. -- The Oakland Athletics had eight rookies in their lineup for the second game of a doubleheader Saturday against the powerful Houston Astros.

Oakland's kids proved they can play.

Rookie outfielder Chad Pinder hit a tie-breaking solo home run in the bottom of the seventh inning and a three-run blast in the eighth, powering the A's to an 11-4 victory against the Astros and a sweep of their doubleheader.

The A's defeated the Astros 11-1 in the opener when rookie right-hander Daniel Gossett (4-8) held them to one run on five hits with a career-high seven strikeouts and three walks over six innings.

Rookie Matt Olson hit a two-run homer in the sixth inning for the A's in the second game. Franklin Barreto, another rookie, went 2-for-4 with a triple, an RBI and a run. Rookie catcher Bruce Maxwell did his part, going 2-for-4 with a double, an RBI and a run. And so did fellow rookie Boog Powell, who went 2-for-4 with a run and three RBIs.

"That's big," Pinder said of sweeping Houston. "That's really big for us and the confidence for our team going forward. They're an incredible baseball team as you guys have seen all year. We played some good baseball today. I think that's something to build off of."

A's rookie right-hander Daniel Mengden gave up three runs (two earned) on five hits over six innings in a no-decision.

"We're young, we're hungry, we want to be here," Mengden said. "We're having a lot of fun and we're winning right now. We'll be a force to be reckoned with pretty soon. We're jelling really nice now. A lot of us played together through each level almost, all the way up. Its' fun to watch."

The Astros lost their third straight game, all to the A's, after winning seven straight. They're still running away with the American League West race, but they fell into a tie with Cleveland for the best record in the AL at 86-56.

"We have a great team," said Astros reliever Chris Devenski, who gave up Pinder's solo home run. "Whatever happened today, we'll put it behind us. Tomorrow's a new day and we'll start fresh tomorrow."

Trailing 4-3, Oakland rallied for two runs in the bottom of the seventh to take their first lead of the game. Barreto lined an opposite-field triple off Devenski (8-4) down the right-field line and scored on Powell's sacrifice fly.

Pinder followed by hitting Devenski's 2-1 slider into the left field seats. It was his 13th homer of the season.

"That was just kind of a big moment for us, I feel," Pinder said. "Got some momentum back on our side there."

In the eighth, the A's, who have defeated Houston four straight times overall, scored six runs.

Pinder capped the explosion with a blast into the right-center field seats off Michael Feliz. The A's had five hits in the inning, including a double by Mark Canha and a two-run single by Powell.

"To go to right-center in this ball park, as far up, it looked like a left-hander hit it," A's manager Bob Melvin said. "We know he's got some power. He showed us that this year. ... He's got power to all field to where all he's got to do is square it up and it's got a good chance to go out."

Chris Hatcher (1-1) pitched two perfect innings in relief for the victory.

Astros right-hander Brad Peacock allowed two runs on five hits over 5 2/3 innings. He struck out nine, walked none and threw 84 pitches in a no-decision.

"Fastball command was good," Peacock said. "I felt good. Everything was working tonight."

Peacock and Mengden were locked in a scoreless pitchers' duel until the top of the sixth when Jose Altuve hit a two-run homer and Josh Reddick hit an RBI single.

The A's answered with three runs in the bottom of the sixth to pull even when Olson launched Peacock's 1-1 curve over the right-center field fence for his 16th home run of the season.

Matt Chapman, yet another A's rookie, greeted reliever Joe Musgrove with a ringing double to right-center and scored on Maxwell double to center.

Houston regained the lead at 4-3 with a run in the top of the seventh on pinch hitter George Springer's sacrifice fly.

NOTES: Astros C Juan Centeno will "miss a few days" and go through the concussion protocol after being injured in the second inning of the doubleheader's first game, Houston manager A.J. Hinch said. Centeno came out of the game after being hit in the head with the bat on A's 2B Jed Lowrie's backswing. "He was a little dizzy when we got on the field," Hinch said. ... The A's had five new starters in their lineup for the nightcap, inserting SS Franklin Barreto, 2B Joey Wendle, LF Mark Canha, C Bruce Maxwell and RF Chad Pinder. ... Houston had six new starters for the second game: CF Cameron Maybin, RF Josh Reddick, 1B Yuli Gurriel, DH Carlos Beltran, C Brian McCann and LF Tony Kemp.