The Texas Rangers are already in the playoffs, and they like their chances to win the AL West.
Two games left, one win needed against Oakland.
"We're upbeat in here. We're not worried about anything," catcher Mike Napoli said. "They made the playoffs, hats off to them. We're worried about winning the division and see what happens."
Coco Crisp's latest big hit helped put the Athletics in the playoffs for the first time in six years, and they remained in contention for a division crown by beating the first-place Rangers 4-3 on Monday night.
Oakland's victory clinched a trip to the postseason and eliminated the Los Angeles Angels and Tampa Bay Rays from playoff contention.
Crisp had a go-ahead double in the fifth inning as the A's (92-68) pulled within one game of Texas (93-67) in the division race with two to go and moved into a tie with Baltimore for the American League's top wild card.
Michael Young and Mike Napoli homered against rookie Jarrod Parker (13-8), who was otherwise solid in beating the Rangers for the third time in three chances.
"We have to win a ballgame," Young said. "Every game has been important for a long time now. We'll come out tomorrow ready to play."
Pinch-hitter Brandon Moss delivered a sacrifice fly for insurance and Josh Reddick added an RBI single for the resurgent A's, who must sweep this season-ending series against the two-time reigning AL champions to capture the West title.
"Absolutely amazing," said manager Bob Melvin, who took a whipped cream pie in the face from Reddick. "We don't get this done unless everybody believes in everybody and everybody plays selflessly."
Crisp followed the double by stealing his 39th base, then scored on Moss' fly ball to shallow center. Center fielder Josh Hamilton hesitated ever so slightly before making the throw home, just enough for Crisp to slide in safely.
"We're just a bunch of young guys having fun," Crisp said, standing in water wearing soggy socks. "You wouldn't think all these rookies would be doing things like this."
Playing to chants of "Let's go Oakland!" from the crowd of 21,162, the gutsy A's won their fourth straight game and sixth in seven. Fans were on their feet chanting as closer Grant Balfour finished it out by striking out the side.
Moments later, players brought bottles of bubbly onto the field and began spraying them into the stands. Outside the aging Coliseum, car horns honked as this blue-collar city enjoyed its big moment on the baseball stage.
"Awesome! Unbelievable," Balfour said mid-celebration. "I want to keep doing it."
Parker pitched the A's back to the postseason for the first time since they were swept by Detroit in the 2006 AL championship series. He matched teammate Tommy Milone for the Oakland rookie record of 13 wins.
Oakland moved a season-high 24 games over .500 for its best mark since ending that '06 season at 93-69.
"They play with no conscious. They're not afraid of nobody right now," said Rangers manager Ron Washington, Oakland's longtime third-base coach before leaving to manage Texas. "I'm never surprised what happens over in that clubhouse with the Oakland A's. They've always got pitching, and when you've got pitching, you never know what can happen."
This one sure had the feel of a fall October playoff game despite the unseasonably warm 82-degree temperature at first pitch.
The Rangers now must wait at least one more day as they try to clinch their third straight division title. Texas won the second game of Sunday's doubleheader at home against the Angels to secure a third straight playoff appearance for the first time in franchise history and sixth overall.
"I'm not sending any message. My team knows what needs to be done," Washington said. "The message was sent yesterday."
Then, the Rangers landed at the Oakland airport about 1:30 a.m. Monday and arrived at their hotel after 2 a.m. Washington said he finally got to bed around 3 a.m. local time.
The AL playoff lineup became a little more clear Monday, with two teams clinching spots. Detroit won earlier in the night at Kansas City to wrap up the AL Central crown.
Parker was done after allowing Napoli's leadoff homer in the seventh. Sean Doolittle retired the next three batters in order and Ryan Cook worked a 1-2-3 eighth through the heart of the Rangers' order. Balfour then earned his 23rd save.
Parker improved to 3-0 with a 2.70 ERA against Texas in his fourth straight winning decision and sixth in seven since a loss Aug. 14 at Kansas City.
Texas starter Martin Perez (1-4), facing the A's for the third time in his six major league starts, allowed back-to-back singles by Crisp and Jonny Gomes in the first before receiving a mound visit from pitching coach Mike Maddux. Perez then got Yoenis Cespedes to ground into a double play before walking Chris Carter ahead of Reddick's single.
The left-hander also was called for a balk with the bases loaded to bring home Oakland's second run. Perez lost his second straight start to the A's after a 9-3 defeat his last time out in Texas.
Rangers third baseman Adrian Beltre was the designated hitter a day after coming out in the seventh inning when he aggravated his strained left shoulder while leaping for a ball with his arm fully extended. Washington said Beltre could play third base Tuesday night.
NOTES: Texas' Nos. 3-5 hitters went 1 for 12 with five strikeouts. ... The A's are 5-2 vs. Texas at home this year and lead the season series 9-8. ... Perez beat the A's for his first major league win June 30. ... Washington gave Melvin his vote for Manager of the Year. "To take that group where they are right now, wow, you've got to admire him," Washington said. "They play like they belong."