The decisive blow was struck with one out in the bottom of the 11th inning, when Emil Brown smacked a walk-off home run to left field against left-handed reliever Cesar Jimenez. But it was the bottom of the ninth inning that determined the eventual outcome.
Right-hander Brandon Morrow, the Mariners' fill-in closer who had not allowed a run since May 27, experienced the agony of a blown save for the first time in his Major League career.
He needed three outs to sustain the two-run lead he inherited, but stunningly, he surrendered a pair of home runs that sent the series finale spinning into extra innings. The first one was a fastball that Jack Cust drove into the right-field seats and then, with two outs, pinch-hitter Kurt Suzuki reversed another fastball, sending it over the fence in left-center for a game-tying blast.
And just like that, after going 8-for-8 in save opportunities since becoming the closer, a "BS,1" was attached to Morrow's pitching line.
"I was missing my spots," he said. "That was the main thing. I didn't have my best fastball, but I fell behind, and when that happens, with me they know what's coming. Both pitches were pretty much right down the middle. It's a bad feeling, but I will come back with the same mentality I've had."
"He has done a great job for us," interim manager Jim Riggleman said. "They put some good at-bats on him and got him. That's about all you can say. After Cust hit the home run, he struck out Brown and [Carlos] Gonzalez and I felt like he was back on the beam. But he threw ball one -- instead of strike one -- and Suzuki got him."
As losses go, this was as tough as it gets -- even for a team that has lost more times than anyone in the American League.
The Mariners are ending the first half of the season the same way they started it -- receiving solid starting pitching but getting little to show for it.
Dickey has done his part time and time again, but still hasn't secured a spot in the rotation.
"I think I have certainly worked hard to be trustworthy in that role," said Dickey, who lowered his ERA to 3.86. "A lot of it is up to what decision they want to make, but four out of seven quality starts isn't too bad. I throw a lot of pitches and can go a lot of innings, and that's a good definition of a fourth or fifth starter."
"He has done a great job," Riggleman said. "He has just been a real factor for us, getting deep into games, but it's tough to get a feel of when to take him out. I really don't know. I'm trying to get a feel for him to see how we can best utilize him.
"He's so durable that he probably will be available [for relief duty] in the Kansas City series."
Dickey said he would probably need Friday off after throwing 116 pitches, but figures he'll be good to go on Saturday or Sunday, if needed.
When discussing how the rotation shapes up coming out of the All-Star break, the Mariners mention Dickey's name merely in passing. But with Erik Bedard on the 15-day disabled list and 37-year-old Miguel Batista's health a factor, Dickey might become a rotation fixture by default.
"I can see him starting; it's almost inevitable," Riggleman said. "It seems we're never going to have all five out there at the same time anyway, so there is going to be a spot there. I can see him continuing to start.
"If he's not starting, the Mariners are in pretty good shape, because it means we have five guys throwing better than him. That would be saying something."
Dickey had a wobbly first inning while adjusting to the pitching mound, loading the bases before wiggling out of the jam. But he settled down quickly and zipped through seven innings, surrendering four hits and four walks.
It took a while for the Mariners' offense to provide the sort of support Dickey so richly deserved.
Finally, second baseman Jose Lopez gave the Athletics double trouble. He doubled and scored the first run of the game in the eighth inning, and ripped a run-scoring double in the ninth as the Mariners took a 2-0 lead.
But for the fourth time this season, a lead carried into the bottom of the ninth inning did not hold up.