A rough month didn't get any better for Texas on Sunday night, even though the game-time temperature of 100 degrees would have seemed to be in the Rangers' favor against Oakland.
However, they trailed 5-0 in the second inning en route to a 9-3 loss to the Athletics. Texas has lost 15 of its last 18 and dropped to 4-19 in July.
Oakland's John Jaso drove in three runs, helping Scott Kazmir to his 12th win -- tied for the American League lead.
"Tonight, it was just the pitching," Texas manager Ron Washington said. "We couldn't muster anything."
The Rangers' own pitching, clutch hitting and fielding, weren't very good either.
Miles Mikolas (1-3) allowed seven earned runs on seven hits and four walks in 4 2-3 innings. He was coming off his first major league win as a starter, over the Yankees July 21.
"I fell into some of the bad habits that we'd been working on in the bullpen," Mikolas said. "I executed well and made the transition well in the New York game, and kind of fell back. I'm going to work on it."
Mikolas made a miscue in the second inning that cost him.
With one out, he walked Jed Lowrie and Eric Sogard. Craig Gentry, the No. 9 hitter, hit a soft grounder to Mikolas, who threw to second hoping to start a double play but the ball went into center field. Lowrie scored on the play.
"I kind of fell away from that throw," Mikolas said. "It was a poor throw, but those kind of mistakes happen."
Jaso and Vogt followed with run-scoring hits. Cespedes doubled to drive in the final two runs.
In the third and fifth innings, Rangers No. 5 batter J.P. Arencibia went to the plate with a total of five runners on base. Kazmir struck him out both times.
Washington said, "That's J.P. I don't think he can change. We gotta live with it."
Arencibia was not available for comment.
Jaso had added a two-run double in the fifth, when Oakland extended the lead to 8-2.
The Athletics' first three batters -- Jaso, Stephen Vogt and Yoenis Cespedes -- each had a double and a single, and Josh Reddick added three singles.
Kazmir (12-3) allowed seven hits in five innings. He walked two and struck out two.
Athletics manager Bob Melvin said: "It was maybe not his best command at times. But seeing him be so good this season, that five-inning outing doesn't look so good."
The victory enabled Oakland to remain two games ahead of the second-place Los Angeles Angels in the AL West. The Athletics are 7-5 against the Rangers this season.
Adam Rosales had a two-run homer in the second for the Rangers that cut their deficit to 5-2.
"Any time you score a couple runs on one hit, you're going to get a little momentum," Rosales said. "But being down by five early in the game it is kind of tough. We tried our best."
Adrian Beltre added a solo shot off reliever Evan Scribner in the eighth. Beltre was 2 for 3 with a double and a walk.
Jaso has an 11-game hitting streak against Texas and a 15-game streak as the Athletics' leadoff batter. He is batting .394 (13 for 33) against the Rangers this season.
"I don't know what it is," the left-handed-hitting Jaso said. "I've hit some home runs here. The warm weather is nice, and they have a lot of righties."
NOTES: Rangers LHP Derek Holland is scheduled to pitch two innings in his first game this season Wednesday on an injury-rehab assignment for Double-A Frisco. Holland, on the 60-day disabled list following offseason surgery on his left knee, threw in the bullpen and took fielding practice before Sunday's game. ... Texas rookie RHP Roman Mendez pitched a perfect eighth inning. He has not allowed a run in 11 innings during his first eight major league games.