OAKLAND -- Baseball's most improbable story of 2012 is complete: The Oakland Athletics are champions of the American League West.
Written off by the experts following an offseason in which young stars were again traded, the A's faced a 13-game deficit as late as June 30 before stealing the division title from Texas, beating the Rangers 12-5 Wednesday.
"The bottom line is we believed we should be here in this situation," center fielder Coco Crisp said, "and that's not going to change."
The A's, who picked up six games in the standings over the final nine days, rallied from an early 5-1 deficit Wednesday. Oakland never held sole possession of first place all season until getting the final out of the season's 162nd game.
Two-time World Series runners-up Texas, meanwhile, led the division for 176 consecutive days until Oakland tied for first Tuesday.
"You've got to play the game between the lines," Rangers manager Ron Washington said. "There were some things along the line we didn't do very well. We accept that and won't make any excuses."
The A's will open the playoffs Saturday or Sunday against an opponent to be determined. The Rangers will play as a wild-card entrant Friday against either the Baltimore Orioles or New York Yankees.
"Today it was win or lose the division," Texas second baseman Ian Kinsler said. "Now it's win or go home."
The Athletics' big fourth-inning rally started when Rangers starter Ryan Dempster issued a walk to Brandon Moss. Three consecutive hits followed to produce two runs -- a double by Josh Reddick along with singles from Josh Donaldson and Seth Smith -- sending the veteran Dempster to the showers.
"They stayed on a couple pitches and got some hits," Dempster said. "I should have done a better job of executing."
Reliever Derek Holland retired the first two he faced, but he couldn't work out of the two-out jam as Crisp placed a double in the right field corner to tie it. Stephen Drew walked before the key play of the inning occurred.
Yoenis Cespedes skied a fly to medium center on a 3-1 pitch, a routine play, but the ball tipped off the end of Josh Hamilton's glove for a two-run error, and the Oakland uprising was complete -- six runs on four hits and a 7-5 lead.
Hamilton explained he usually slows down when he settles under a ball hit like Cespedes'.
"I didn't do that. I continued running basically at the same speed and just missed it," Hamilton said. "No excuse for it, but it happened, and I can't take it back."
The comeback was necessary because Texas quieted the standing-room-only crowd of 36,067 early with a five-run rally in the third inning.
David Murphy drove in two with a single as the Rangers appeared to seize control of the game early, especially after Dempster set down Oakland 1-2-3 in the bottom half of the frame. But the Rangers couldn't tack on against Oakland's stingy bullpen.
"They took advantage of the opportunities presented to them," Washington said. "We just didn't take advantage of the opportunities presented to us."
Oakland catcher Derek Norris hit an RBI single in the fifth inning to give the A's a three-run advantage. And Norris, who didn't start, hit a leadoff homer on an 0-2 pitch to kick-start a four-run rally in the eighth to put the game out of reach. Moss supplied a two-run single in the inning.
Right fielder Josh Reddick complimented A's manager Bob Melvin for pulling the group together.
"He's done a great job," Reddick said. "All the platoons he's had to put together and all the rookies he's had, he's done something nobody thought he could bring together."
Oakland's bullpen supplied clutch relief. Evan Scribner tossed three innings of two-hit, shutout ball. Jerry Blevins struck out Hamilton to get the final out of the sixth. Ryan Cook pitched out of a two-on, none-out jam with an infield groundout and a pair of strikeouts in the seventh.
It was Sean Doolittle's turn in the eighth. After he got the first two Rangers, Doolittle flashed a flair for the dramatic by striking out Hamilton after teasing Texas with a walk issued to Andrus. Grant Balfour, pitching for the fifth day in a row, threw a 1-2-3 ninth to close out the regular season.
"I don't think there's one guy in here who hasn't dealt with adversity, so we'll deal with it and hold our head up high," Kinsler said. "Now instead of having to win 11 games, we have to win 12."
NOTES: The A's are the fifth team to come back from a deficit of 13 or more games to win a pennant or division title. ... Oakland hit a major-league-leading 112 home runs after the All-Star break. ... The A's have won 15 AL West titles. ... Dempster threw three-plus innings, his shortest stint of the season.