Texas Rangers (93-67) at Oakland Athletics (92-68), 10:05 p.m.

Probable Starting Pitchers: Texas - Matt Harrison (18-10, 3.26) Oakland - Travis Blackley (5-4, 4.25)

(Sports Network) - With their first postseason spot in six years secured, the Oakland Athletics now set their sights on a bigger prize. The A's try to move into a first-place tie in the American League West on Tuesday in the middle test of a three-game series against the Texas Rangers at the Coliseum.

Oakland secured its first playoff appearance since 2006 in Monday's opener, as Coco Crisp had two hits, including a go-ahead RBI double in the fifth inning, and scored twice to help the A's win, 4-3.

The hard-charging A's, who have won seven of their last nine games, need to sweep Texas in order to win the American League West crown.

"Absolutely amazing," Oakland manager Bob Melvin said. "We don't get this done unless everybody believes in everybody and everybody plays unselfishly."

Crisp returned to the lineup Friday after missing nine starts with an infection in both eyes. He's hitting .529 (9-for-17) with seven runs and two RBI in four games since coming back.

Jarrod Parker (13-8) fanned six and surrendered three runs on six hits and two walks over six-plus frames to pick up the win.

Pitching to chants of "Let's go Oakland!," Grant Balfour struck out the side in the ninth and notched his 23rd save of the season.

"They play with no conscience. They're not afraid of nobody right now," said Rangers manager Ron Washington.

Martin Perez (1-4) allowed four runs on six hits and two walks in four-plus innings for Texas, which holds a one-game lead over Oakland and is tied with the New York Yankees for the best record in the American League. The Yankees defeated the Boston Red Sox earlier on Monday.

The Rangers can lock up their third straight division crown on Tuesday behind lefty Matt Harrison, who is 18-10 with a 3.26 ERA. Harrison beat Oakland on Thursday, despite allowing four runs in six innings.

"I just want to do what I've tried to do all year, give us a chance to win by putting up as many zeros as possible," Harrison said. "That team is playing good baseball so it will be a tough start. But I feel confident I can go out and get the job done."

He is 6-1 lifetime versus the A's with a 4.13 ERA in 12 games (9 starts).

Oakland, meanwhile, will counter with lefty Travis Blackley, who lasted just one inning in a loss to the Rangers on Thursday. He was hit for five runs and five hits - 2 HRs - in that one and fell to 5-4 on the year to go along with a 4.25 ERA.

"The last time they just hit him, and that's going to happen," Melvin said. "You have to keep having faith in him and confidence in him. We're going to continue to support him and have confidence in him, and if he has a bad game or two, that's not going to change how we feel about him."

Blackley has faced the Rangers five times and is 2-2 with a 6.85 ERA.

Oakland is 9-8 against Texas this season.