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Oakland righty Jarrod Parker tries to lead the Athletics to a three-game sweep of the Texas Rangers on Wednesday when the American League West foes finish their set at Rangers Ballpark in Arlington.

Oakland continued to slice into Texas' division lead on Tuesday, as Yoenis Cespedes homered for the game's only run and Dan Straily spun seven stellar innings of two-hit ball to lift the A's to a 1-0 win.

Cespedes launched his ninth home run of the season with two away in the third, while Straily (2-2) struck out five without walking a batter to earn his first victory since his initial start of the season on April 5.

"Best pitching performance we've seen out of him to date," A's manager Bob Melvin said of Straily. "Really aggressive today."

Sean Doolittle worked around a two-out single in the eighth before Grant Balfour fired a perfect ninth to notch his ninth save and secure Oakland's fifth straight triumph.

Texas' offensive struggles spoiled a solid start from Yu Darvish (7-2), who scattered five hits and three walks over six frames to absorb his second loss of the season and first since April 12.

A.J. Pierzynski, who was activated off the disabled list before the game, registered one of the three hits for the Rangers, who have dropped back-to- back games to the A's after taking two of three from their AL West rivals in Oakland last week.

"He was okay. He wasn't, obviously, as sharp as he'd been," Pierzynski said of Darvish. "He really only made one mistake and that was the ball that the guy hit for the home run."

Texas still leads the AL West by 4 1/2 games over the A's, who hope Parker gives them as good of an outing as he did his last time out.

Parker was terrific against Kansas City on Friday, but did not get a decision, despite allowing just a run and four hits in seven innings of the A's 2-1 win.

He is 2-5 on the year with a 6.04 ERA.

Parker is a perfect 3-0 against the Rangers with a 2.70 ERA in three starts.

"He's a very good pitcher. He can spin the breaking ball, throws strikes and changes speeds," Texas manager Ron Washington said of Parker. "He's tough, very tough. His changeup is his masterpiece. It's one of those that you know is coming and you still can't do anything with it. His changeup is superb, and he's not afraid to throw it."

Texas, meanwhile, will hand the ball to righty Ross Wolf, who will be making his first ever big league start. The Rangers had hoped to have Nick Tepesch go in the finale, but he was scratched due to a blister on his right middle finger.

So, instead it will be Wolf, who has been a part of five organizations and spent nearly his entire 12-year professional career in the minors. He hasn't pitched since 2010 with the A's when he pitched to a 4.26 ERA in 11 relief appearances.

However, he has pitched well this season for Triple-A Round Rock, with a 1.85 ERA in six starts.

"He's one of the hottest guys down there," Washington said. "We're going to give him a chance while he's throwing the ball well and hope he can continue it."

The A's have won three of their five matchups with the Rangers this season.