ARLINGTON, Texas -- Adrian Beltre and the Texas Rangers put themselves in good shape for their big four-game series starting Monday against the Houston Astros.

Beltre homered twice and drove in five runs as the Rangers pounded the Oakland Athletics 12-4 Sunday to set the stage for their American League West showdown.

The win kept the Rangers 1 1/2 games behind the Astros in the West, while the loss clinched a losing record for Oakland (61-82) for the first time since 2011.

Beltre, who entered the game in a 5-for-38 slide, drilled a two-run homer off Oakland starter Felix Doubront (3-2) in the fourth inning that put Texas up 3-0. An inning later, he got to Doubront again, clubbing a three-run homer to right center as part of a five-run fifth for the Rangers that put them up 8-0.

The big offensive output -- which included matching season high with four home runs -- was good for a Texas team that had lost three of four games with two of those setbacks coming in shutouts.

"It was a good game for everybody," said Beltre, who had his first two-homer game of the season and also set a season high with five RBIs. "It was a good game all around for our offense. We were kind of slipping for the last couple of games. Today was a good awakening. Everybody contributed and it was just nice to see. It's big to take that to tomorrow's game."

The big inning made a winner out of rookie right-hander Chi Chi Gonzalez (3-5), who allowed three runs (one earned) in his 5 1/3 innings of work. Gonzalez allowed two hits, struck out two and walked three.

Gonzalez was able to relax a little after getting some offense early. The Rangers took a 1-0 lead in the first inning on a homer from Shin-Soo Choo and then Beltre's homer in the fourth gave him more support to work with.

"I just take it as another outing and control what I could control," Gonzalez said. "After that first inning I just tried to get the ball and go. The offense did well and scored me runs and played defense well, too."

The Rangers had 12 hits, with Choo going 3-for-4 with three runs scored and two RBIs. Second baseman Rougned Odor capped the Texas scoring with a three-run homer in the eighth.

Doubront is now 0-5 in his career against Texas, but manager Bob Melvin didn't think he pitched poorly despite allowing seven runs in 5 1/3 innings.

"Actually, it might have been the best command we've seen since he's been here," Melvin said. "He just got a couple of balls in the wrong spot to Beltre. You give up some home runs with multiple guys on base, end up being big innings."

Beltre is 7-for-11 lifetime against Doubront, and the left-hander knows the two at-bats changed the complexion of the game.

"You have to keep that ball down to him," Doubront said. "You can't leave any mistakes around the zone because you're going to pay for it."

The game took 3 hours, 52 minutes -- the longest nine-inning game of the season for Texas -- but the end result was worth it.

"Today was a grind," Texas manager Jeff Banister said. "We talk about not looking ahead, not getting ahead of ourselves and staying focused on today. We have done a tremendous job at that, our guys have stayed focused on today's game, but they're well aware of the next four days."

Oakland got on the board with three runs in the sixth inning. Third baseman Danny Valencia had a two-run triple and designated hitter Billy Butler a run-scoring single. Catcher Carson Blair homered in the seventh for his first major league hit.

NOTES: Texas put Mike Napoli in the starting lineup in left field on Sunday. It marked the first time in his professional career that Napoli started a game in the outfield. ... Right hamstring tightness kept Oakland OF Billy Burns out of the lineup for a third consecutive game. There's a chance he'll play again Tuesday in Chicago. ... The Rangers have started six different players in left field in the last nine games. ... Texas C Robinson Chirinos still has soreness in his left shoulder after injuring a biceps tendon while taking a foul ball off the shoulder last Wednesday. He hopes to resume throwing in the next few days. ... Saturday night's win over Texas clinched the season series for Oakland. The A's have now won the season series against the Rangers three of the last four years.