Jackson barely beat a double-play relay in the 11th inning as the winning run scored, sending the Mariners over the Los Angeles Angels 2-1 on Saturday night and forcing the American League wild-card chase to the final day.
"It felt -- I really can't explain it," Jackson said. "It really didn't set in even when he said, 'Safe.' It was such a long game, and we had a lot of opportunities."
The Mariners moved within one game of Oakland for the second AL wild-card spot. The A's lost 5-4 at Texas.
Seattle ace Felix Hernandez will start against the AL West champion Angels on Sunday, the last scheduled day of the regular season.
Jackson had failed to convert several opportunities earlier in the game, twice making the third out in innings when Seattle stranded runners on third.
Jackson hit a grounder to second baseman Grant Green with the Angels playing five fielders in a drawn-in infield.
"Luckily, I was able to make contact and run as hard as I could," Jackson said. "I kind of wanted to dive at the base and grab it."
Mariners manager Lloyd McClendon could do nothing but watch.
"It felt like that play took about an hour and a half," McClendon said. "I think my heart stopped maybe two or three times."
Green seemed to think about throwing home for a split second before trying for the double play.
"He was a little bit indecisive," Los Angeles manager Mike Scioscia said. "I don't think you really have time to second-guess yourself, and that's kind of what he did there."
The Angels got the forceout at second. But the relay from Shawn O'Malley, who'd moved in from left field to near the bag, was a shade late as the speedy Jackson crossed.
Miller raised his arms as he scored the winning run, giving the Mariners a shot at the postseason going into the season's final day.
"We've got to go out and just play with the same energy we did today," Miller said. "We've got the best guy in the league on the mound tomorrow, so we've got to take care of our business, but that's where you want to be."
Dominic Leone (8-2) pitched the 11th to earn the win.
Seattle entered the game needing to win its final two games and Oakland to lose its final two in order to tie for the second AL wild-card spot and force a one-game playoff at home Monday.
"We've got to hope Oakland loses," McClendon said. "But we're playing a meaningful game at 162, and I think that speaks volumes about this organization, and about this club and the direction we're headed."
The Athletics' loss in Texas finished at nearly the same moment as Seattle tied the game at 1 on Logan Morrison's RBI double in the seventh. Morrison was stranded on third when Jackson struck out to end the inning.
Seattle had the bases loaded with no outs in the bottom of the ninth on Los Angeles reliever Jason Grilli and couldn't get a run across.
Grilli struck out Miller and Taylor before getting Jackson to fly out and send the game to extra innings.
The Angels, who clinched home-field advantage in the playoffs Friday, pulled most of their regulars in the seventh and eighth innings.
Angels: OF Josh Hamilton, who has played just one game since Sept. 4 due to a sore muscle in his side and a sore shoulder, will hit from a tee and take soft toss tomorrow, Scioscia said. ... RHP Matt Shoemaker (oblique) felt good after a long-toss session Saturday and might throw from a mound Sunday.
Mariners: Starter Hisashi Iwakuma left Friday's game in the middle of an at-bat in the seventh inning with discomfort in his side but is fine, McClendon said.
Angels: RHP Cory Rasmus (3-1) will take the mound for Los Angeles' final regular-season game. It will be the sixth start for Rasmus, who is 0-0 with a 1.69 ERA as a starter.
Mariners: Hernandez (14-6) has a chance to take the AL ERA title Sunday. A scoring decision Saturday charged Hernandez with an error in Tuesday's 10-2 loss at Toronto, a play originally called a hit. The change removed four earned runs from Hernandez's record, dropping his ERA from 2.34 to 2.18 going into his final start of the regular season. Chris Sale of the Chicago White Sox, who made his final scheduled start Wednesday, leads the AL at 2.17.