OAKLAND, Calif. -- The Texas Rangers had high hopes when left-hander Cole Hamels took the mound Saturday afternoon against the Oakland Athletics.

Hamels had a five-game winning streak and a 9-1 record this season.

But in the bottom of the first inning, A's rookie Chad Pinder hit a solo home run off Hamels, then he hit another solo shot in the third.

Left-hander Sean Manaea pitched five strong innings to end his three-game losing streak, and the Athletics rolled to an 8-3 victory over the Rangers at Oakland Coliseum.

The last-place A's beat the wild-card playoff-contending Rangers for the second straight time and will go for a series sweep on Sunday afternoon. Texas (64-65) remained two games behind Minnesota (66-63) for the second wild-card spot in the American League.

Hamels (9-2) gave up six runs and nine hits in 4 1/3 innings, matching his shortest outing of the year. He struck out two, walked three and had two wild pitches. The nine hits allowed matched his season high.

"Putting us in a situation like this is obviously not what I like to do," Hamels said. "It's tough. You have to make good pitches, you have to battle. It's not going to be easy to get a win, no matter how you look at it. You really have to grind away and especially where we are in the season.

"We've had a good road trip so far. Yesterday was a tough loss and obviously with what I was not able to get done today makes it even tougher."

The A's beat Texas 3-1 on Friday night when Khris Davis hit two solo home runs.

Pinder followed suit on Saturday with his 11th and 12th homers of the season. The multi-homer game was Pinder's second of the season and his career. He homered twice at Cleveland on May 31.

"I've had some success against him and was just able to take advantage of a couple mistakes he threw me," Pinder said.

Pinder is 4-for-6 with two homers, two doubles and a walk in two career games against Hamels.

Jed Lowrie went 2-for-3 with two doubles and three RBIs for the A's.

Elvis Andrus went 3-for-5 with a double and scored a run for the Rangers. Adrian Beltre had a two-run double and three RBIs. Carlos Gomez (excision of a cyst behind his right shoulder) was activated from the disabled list and went 0-for-3.

Manaea allowed two runs and seven hits, struck out three and walked one. He won for the first time since July 16 at Cleveland. In his previous six starts, Manaea was 0-3 with an 8.17 ERA.

"The past couple of starts I'm trying to find things that are working out," Manaea said. "You have to grind through these things and limit the damage the best you can. There were times I really had to bear down and thankfully I was able to make some pitches and let the defense work. I tried to relax, knowing I can't be perfect every pitch."

The Rangers took a 2-0 lead in the top of the first inning by using Delino DeShields' leadoff single and back-to-back doubles by Andrus and Beltre.

Pinder cut the Rangers' lead to 2-1 in the bottom of the first when he launched Hamels' 2-0 fastball over the center-field fence.

The A's pulled even in the third on Pinder's second solo shot to center. This time, he hit a 1-2 changeup from Hamels.

"Well, challenging for Cole today," Rangers manager Jeff Banister said. "It seemed like he struggled with the rhythm and timing of his delivery. He made mistakes across. When they were trying to go away it seemed like the ball leaked back out over the plate.

"It seemed like their lineup gained a little energy off of the couple home runs by Pinder and then late in the last inning for Cole couldn't get the outs when we needed them."

Oakland took a 3-2 lead in the fourth. Matt Chapman beat out an infield single with two outs and scored on Matt Joyce's sharp single that ricocheted off Beltre's glove at third into shallow left field.

The Rangers loaded the bases with two outs in the fifth, but Manaea struck out Mike Napoli on a 3-2 changeup, two pitches after Napoli hooked a fastball into the upper deck in foul territory.

Texas went 1-for-9 with runners in scoring position and left nine runners on base.

"We have created situations, but we haven't been able to bring them home," Beltre said. "We had plenty of chances today and yesterday and didn't come through."

The A's increased their lead to 6-2 in the bottom of the inning, scoring three times and knocking Hamels out of the game.

Marcus Semien drilled a leadoff double and went to third on a wild pitch. After Pinder walked, Lowrie sent an RBI double to right center. Davis brought Pinder home with a sacrifice fly, and Ryon Healy grounded an RBI single to center to make it 6-2 and end Hamels' day.

Oakland made it 8-2 in the sixth when Lowrie hit a two-run double.

NOTES: Rangers INF/OF Joey Gallo said he "feels really good" and expects to be activated from the seven-day concussion DL on Tuesday, the first day he is eligible. "My mind's clear," he said. Gallo, who leads the Rangers with 35 home runs, has been taking batting practice but said it might take him a game or two to regain his timing and rhythm at the plate. ... INF Phil Gosselin was optioned to Triple-A Round Rock. The Rangers signed Gosselin off waivers from the Pittsburgh Pirates on Aug. 12. ... A's OF Mark Canha started in center field for the seventh time in his major-league career. OF Rajai Davis had started in center against left-handed pitchers before being traded to Boston on Wednesday. Canha is vying for that role, but INF/OF Chad Pinder will also get some time in center field. ... The A's honored Hall of Fame pitcher Dennis Eckersley during a pregame ceremony. Eckersley threw out the first pitch, and 15,000 fans received an Eckersley bobblehead.