The American League playoff teams are set. All that remains to be determined are the first-round matchups.

After three days of waiting, the Oakland Athletics clinched the AL West title Tuesday night when they beat the Mariners 12-3, setting off a wild celebration in Seattle that lived up to the Athletics' frat house reputation.

Nick Swisher and Milton Bradley each homered in a four-run second to back Rich Harden's five shutout innings. The win, combined with the Los Angeles Angels' 5-2 loss against Texas, sent the small-budget A's back to the postseason after a two-year absence.

“This is a team. We've had injuries all year long and people in baseball were wondering how this team was going to win,” slugger Frank Thomas said. “We have a group of guys that care about each other and we stuck together all year long and found a way.”

Oakland earned its first AL West crown since 2003 and the 14th in franchise history thanks to a sensational second half - a hallmark for this club in recent years.

The New York Yankees, Detroit Tigers and Minnesota Twins already wrapped up playoff berths as well, but the division series matchups won't be certain until the AL Central race is decided.

The Tigers lead the Twins by one game with five to play. Detroit also won the season series against Minnesota and would win the tiebreaker if they finish with the same record.

The star-studded Yankees, with a $200 million payroll, are no surprise. But the Tigers ($82 million) began the season with the 14th-highest payroll in the major leagues, while the Twins ($64 million) ranked 19th and Oakland ($62 million) was 21st.

So much for small-market teams not having a chance.

Oakland could have wrapped up the division title at home last weekend, but it dropped two straight games to the Angels. Los Angeles then beat Texas on Monday night, while the A's blew a 9-3 lead and lost to Seattle, keeping their magic number at two for the third day in a row.

But Oakland broke out to a big lead Tuesday and celebrated after the final out, bouncing together in the middle of the infield. Then the A's went back to the clubhouse for a raucous party.

No one was immune from the champagne and beer flying from every direction - coaches, clubhouse assistants and even the players' wives who ventured in to join the fray.

Next up, the A's will try to advance to the AL championship series following four first-round exits from 2000-03.

The Angels, meanwhile, are headed home this October after winning consecutive AL West titles the past two seasons.

Harden (4-0) was staked to an early 5-0 lead. Making just his second start since June because he was on the disabled list with an elbow injury, the right-hander showed he's ready for the postseason, allowing only two singles and striking out five.

Rangers 5, Angels 2

At Anaheim, Calif., Robinson Tejeda (5-4) pitched 6 2-3 strong innings and Mark Teixeira hit a two-run homer for Texas. Kelvim Escobar (11-14) allowed five runs and seven hits in 1 2-3 innings - his shortest outing this season. Wes Littleton pitched two perfect innings for his first career save.

Tigers 4, Blue Jays 3

At Detroit, Placido Polanco drove in three runs, Jeremy Bonderman (14-8) pitched six solid innings, and Detroit (95-62) remained tied with the Yankees for the best record in baseball.

The Tigers have won eight of 11 after a prolonged slump. Bonderman has won three straight starts after going 0-4 in his previous nine. Todd Jones earned his 37th save.

Twins 3, Royals 2

At Minneapolis, Johan Santana (19-6) pitched eight strong innings in his final start before Game 1 of the playoffs. The AL Cy Young Award favorite improved to 16-0 over his last 23 starts at the Metrodome. The Twins haven't lost one of his home starts since Aug. 6, 2005.

Joe Nathan escaped a bases-loaded jam in the ninth for his 36th save. The Royals dropped their eighth straight, and one more defeat will give them a third consecutive 100-loss season.

Yankees 5, Orioles 4

At New York, Cory Lidle (4-3) pitched neatly into the seventh inning in a playoff audition, Bobby Abreu and Robinson Cano homered and the Yankees held off Baltimore. Scott Proctor pitched the ninth for his first major league save.

Rodrigo Lopez (9-18) lost in relief of Hayden Penn, who left in the fourth because of a strained lower back. Lopez leads the majors in defeats. His loss total is the most for an Orioles pitcher since Pat Dobson dropped 18 games in 1972.

Red Sox 5, Devil Rays 1

At Boston, David Ortiz hit his AL-leading 54th homer to help Curt Schilling (15-7) earn his first victory since Aug. 4. The Red Sox snapped a three-game skid.

Jason Hammel (0-5) got the loss.

Indians 6, White Sox 0

At Cleveland, C.C. Sabathia (12-11) tied a career high with 11 strikeouts and Ryan Garko homered and drove in a career-best five runs. Sabathia improved to 4-0 this season and 12-3 in his career against the White Sox, allowing four hits over eight innings without a walk. He retired his last 10 batters.

Javier Vazquez (11-11) struck out 12 but dropped to 0-5 in eight starts since beating the Yankees on Aug. 10. The White Sox lost for the ninth time in 12 games.