Seth Smith drove in five runs -- including a two-run double to cap a six-run ninth inning -- as Oakland outslugged Baltimore, 14-9, in the opener of a three-game series at Camden Yards.
Chris Carter hit a two-run homer, Coco Crisp added two hits, two RBI and two runs scored, while Brandon Hicks hit a solo shot and Jemile Weeks knocked in the go-ahead run for the Athletics, who have won 17 of 20 since the start of July to remain in the thick of the AL West race.
"This was a character building game, but we've had a lot of those," Smith said. "Guys are professional and they're going to give everything they've got until the last out is made. That's what we expect, and we have to keep guys here that are willing to do that."
Jerry Blevins (4-0) tossed a scoreless inning of relief for the win.
Adam Jones slugged a three-run blast, Chris Davis posted a solo homer and J.J. Hardy knocked in three for the Orioles, who have dropped four of five.
Jim Johnson (1-1), the AL leader in saves, took the loss and the blown save, charged with five hits and six runs while recording just one out.
The reliable closer came in holding a 9-8 lead, but it all exploded in a matter of minutes.
After Yoenis Cespedes grounded out, Carter, Brandon Inge and Derek Norris singled, the latter tying the game. Pinch-hitter Brandon Moss walked to load the bases, then Weeks knocked in Inge for a 10-9 game. Crisp then plated two more before Luis Ayala was called in.
He served up Smith's two-run double and Oakland had a five-run lead.
"The other team is good too," Orioles manager Buck Showalter said. "They're playing as good as anybody and everything is going their way. That's the way it goes sometimes, maybe tomorrow the breaks will go our way."
Blevins allowed hits to Mark Reynolds and Omar Quintanilla, but Josh Reddick saved the day for the final out. He tracked a Nick Markakis fly to the wall in right, caught the ball while leaping into the padding, but crashed to the warning track where he remained for several minutes before being carted off the field.
Reddick was listed as day-to-day with a back contusion.
Oakland put up four runs in the first on an RBI triple from Reddick, O's starter Zach Britton's wild pitch that scored him, plus a two-run shot from Carter.
Hicks began the next frame with his second homer of the season, but Davis popped a one-out solo shot to right center in the home half.
Baltimore climbed within 5-2 in the third as Markakis drew a two-out walk and scored on Hardy's double off the top of the wall in left, then the hosts took the lead in the fifth.
Taylor Teagarden and Markakis hit back-to-back one-out singles, then Hardy brought the former in on a base hit to make it 5-3. After Jim Thome fanned, Jones barely cleared the left-field wall for a line-drive, three-run shot.
The A's struck back in the sixth. Hicks, Weeks and Crisp all walked with two outs and Smith cleared the bases with a pinch-hit double to make it 8-6.
The O's had the bases loaded with two down in the seventh, but Wilson Betemit struck out swinging.
A three-run rally in the last of the eighth, all with two outs, turned a two- run deficit into a one-run edge. Hardy and Thome stroked back-to-back RBI singles, and after Jones was hit, Davis drove in the lead run on a single, but Thome was tagged out trying to score to end the frame.
The 23 combined runs were the most scored between the two clubs in one game since a 13-12 victory by the Athletics in 10 innings on June 19, 2000 in Oakland...Athletics starter Jarrod Parker served up eight hits and six runs with eight strikeouts over five innings, and Britton was charged with six runs on six hits in 5 2/3 frames...Prior to the game, the Orioles recalled pitcher Miguel Socolovich from Triple-A Norfolk and designated pitcher Dana Eveland for assignment...Game time was four hours exactly.