SEATTLE -- For one night, optimism returned to the Mariners' clubhouse, even if their chances at climbing back into the playoff race at this point are slim.
Jones led off the eighth inning with a pinch-hit home run to pull Seattle even at 5, and Betancourt singled home pinch-runner Charlton Jimerson with two outs in the ninth, setting off a mob celebration in the infield.
"Hopefully this is a wake-up call, and we can start winning games from here on," Jose Guillen said.
It was the type of victory the Mariners needed a week ago, when they were still contenders in both the AL West and wild-card races. The victory was only their third in the past 18 games and they remained 6½ games back of New York in the wild-card chase.
"These guys battled back. They showed a lot of heart," a relieved Seattle manager John McLaren said.
Jones drove a 1-2 pitch from reliever Alan Embree just over the 385-foot sign in right-center field for his second home run since being called up from Triple-A Tacoma on Aug. 3.
Jones had faced Embree on Monday night, and the left-hander tried to jam the youngster with pitching inside. After fouling off a couple of pitches, Embree threw what he thought was a perfectly placed pitch. It looked perfect to Jones, too.
"Maybe we can ride this the rest of the season," Jones said.
Jones was actually the second option for Seattle. Originally it was going to be Jeremy Reed pinch-hitting and facing Santiago Casilla. When Oakland manager Bob Geren saw Reed on deck, he called for Embree and McLaren countered with Jones.
Embree finished the eighth and got the first out of the ninth before handing off to Andrew Brown. Guillen greeted Brown (2-2) with a single to left and went to second on Ben Broussard's slow grounder to second. Brown intentionally walked Jose Vidro and Jimerson pinch-ran for Guillen.
Betancourt then lined an 0-1 pitch from Brown into center field, easily scoring Jimerson from second.
"When he first hit it, I thought we had a chance," Brown said. "But he got inside the ball and it tailed off and away."
Seattle closer J.J. Putz (3-1) pitched a perfect ninth inning. It was only his fourth appearance since he last recorded a save on Aug. 24.
Oakland was in line to hand Seattle yet another crushing loss thanks to a pinch-hitter of its own and Seattle's shaky bullpen.
Reliever Eric O'Flaherty took over in the seventh, but allowed two hits, a walk and recorded only one out. Jon Huber got a key strikeout of Mark Ellis, but Mike Piazza gave Oakland the lead with a pinch-hit, two-run single, his first hit in six at-bats as a pinch-hitter this season.
A's starter Dan Haren nearly made it through the seventh, leaving with two outs after Vidro's bloop double put runners at second and third. Casilla got Betancourt to ground out to end the threat.
Casilla was set to start the eighth before Geren made his switch to Embree. Jones' blast was the second pinch-hit home run this season for Seattle.
"He's got a chance to be a really great player," McLaren said of Jones. "That was an impressive at-bat."
Ichiro Suzuki's two-out RBI single in the sixth scored Betancourt to give Seattle a 4-3 lead and made up for Suzuki's first error of the season an inning earlier. Seattle also got a clutch hit from Ibanez in the third. It was a two-out, two-run double -- the type of hit missing during the Mariners' slide.
The chance at a big inning ended when Swisher saved two runs with a fine diving catch of Guillen's sinking liner. Vidro also ran the Mariners out of two possible runs, twice getting thrown out at home on ground balls to third.
Seattle starter Miguel Batista wasn't exactly efficient. He let the leadoff batter reach base in each of the first five innings and threw 106 pitches in his six innings. But Batista got a pair of key inning-ending double plays and allowed two earned runs and eight hits.
Stewart had four hits and scored three times for Oakland. Swisher drove in two runs and Kurt Suzuki had an RBI single in the fourth.
Haren gave up 12 hits for the second successive start but allowed only four earned runs. He struck out six.
Over the past 18 games, Oakland starters have only two victories, both by Joe Blanton. Haren was in line for the third until Jones' homer. ... Huber was activated off the DL before Wednesday's game after missing three months with a strained right forearm.