ARLINGTON -- Colby Lewis is about as laid back as any Ranger, so to hear him downplay what has become a frustrating attempt at his 10th victory -- he's up to eight tries now -- is hardly surprising.

But then to hear him lash out at Rangers fans after an 8-2 loss to the Oakland A's -- that served as an unusual moment after Sunday's loss.

Lewis, who has had fan sentiment on his side after being a hard-luck loser for his past seven starts, said he heard boo birds after walking Oakland first baseman Daric Barton with two outs in the top of the sixth. That set Lewis off in his postgame interview with reporters.

"It's kind of unfortunate," Lewis said. "It's a situation where I walk a guy there with two outs in the sixth and then you get booed. That's kind of unfortunate, too.

"We should have a little bit better fans than that, you know. I mean we're up by 7 1/2 games now on the Oakland A's and I don't know, I kind of felt disappointed a little bit when our fans booed a little bit. It's the first time I've given up more than five runs. I guess they expected perfection every time."

The 37,188 fans in attendance may have been more upset about the Rangers letting the A's creep within 7 1/2 games in the American League West than a rare poor effort by Lewis and a sloppily played game in the field. The A's certainly were feeling like they were back in things after back-to-back wins over the weekend.

"That's very doable with a month left in the season," A's second baseman Mark Ellis said. "It's not easy to close out the division, I know that from experience. We're just going to keep playing and see where we end up at the end of the year. We needed these two games, there's no doubt about it. The season wouldn't have been over, technically, but it's nice to win these two games."

Lewis allowed six earned runs on eight hits, and it was his own throwing error in the fifth inning that allowed Oakland to open up the lead.

Already trailing, 2-1, with runners at first and second and one out, Lewis fielded a ground ball and threw to second base. Shortstop Andres Blanco was there to cover second , but Lewis' throw sailed into center field and Cliff Pennington motored around from second to make it 3-1.

"I made that little throwing error and things kind of escalated," Lewis said. "It was just a normal play. I make it 10 times out of 10. I told myself to set my feet and make a throw and I didn't make a throw.

"I don't think it was a turning point in the game. I think it was just a situation where I gave up eight hits and two of them were hard hit. They kind of singled me to death. I don't know."

Jorge Cantu, who struck out in each of his first three at-bats and grounded into the game-ending double play, added to the problem when he had a sharply hit ground ball hit to him at first base. He stepped on the bag, but instead of throwing home to cut down Barton, Cantu threw to second base, and while he got Kurt Suzuki in a rundown to end the inning, it allowed Barton to touch home plate before the final out was recorded and Oakland took a 4-1 lead.

"The teams' execution in the final month has to go up," third baseman Michael Young said.

Meanwhile, the Rangers couldn't get anything going against another A's left-hander -- Gio Gonzalez. They were shut down by Dallas Braden on Saturday, and Gonzalez came out with a devastating combination of fastballs and curve balls to stymie Ranger hitters. The Rangers had five hits in six innings against Gonzalez.

"He has good stuff," Rangers outfielder David Murphy said. "He has one of the better curve balls of any left-hander in the league. When he's throwing his fastball for strikes and keeping his curve ball down, he's tough."

Josh Hamilton provided all the offense for the Rangers. He had a two-out RBI single in the third inning and a home run with one out in the bottom of the sixth to cut the A's lead to 7-2. It was Hamilton's team-leading 31st home run.

"If we were going to win today, it was going to have to be a 3-1 or 2-1 game," Rangers manager Ron Washington said.

That left little room for error for Lewis, who struggled with his command after starting the game with three solid innings. He allowed three walks and also gave up two solo home runs. Ellis hit one to left field in the fourth inning to give the A's a 2-1 lead. And Kevin Kouzmanoff made it 5-1 with a home run to start the sixth inning.

Sunday's start was a departure from the Lewis' recent run of hard-luck losses. He had a 0-5 record in his past seven starts, but he also had a 3.33 ERA. The Rangers have now scored two runs or less in seven of his past eight starts, and in most of those starts he's faced one of the AL's top starters.

Lewis is now 0-3 against Oakland and before Sunday's rare poor start, he hadn't allowed more than three earned runs in a start against the A's. Lewis stopped just short of blaming lack of run support for his woes against Oakland, even though the Rangers have scored a total of four runs in three of those losses.

So you can't blame Lewis for what was a day of frustration.

"You can do the numbers," Lewis said. "It's a situation where, before today, I don't think I've give up more than three runs. I don't know, like I said, you can look at the numbers."