OAKLAND, Calif. (AP) _ Matt Stairs hit a three-run homer in the ninth inning as the Oakland Athletics rallied from a five-run deficit to beat the Seattle Mariners 9-7 on Friday night.

Oakland, which trailed 5-0 after three innings, was behind 7-6 entering the ninth. Pinch-hitter Terrence Long led off with a single off Kazuhiro Sasaki (1-2) and moved to second on a sacrifice bunt by Randy Velarde.

Jason Giambi was intentionally walked setting up the game-winning hit by Stairs, who got into the game when Olemdo Saenz left in the second inning with a sprained left ankle.

Stairs hit a 1-0 pitch over the fence in right-center for his fifth home run. He threw his right hand in the air as he rounded the bases.

T.J. Mathews (2-2) got two outs for the win as Oakland moved into sole possession of first place in the AL West this late in the season for the first time since winning the division in 1992. The A's lead Seattle by a half-game.

Edgar Martinez hit a three-run homer and Alex Rodriguez drove in three runs for Seattle.

Ramon Hernandez hit a two-run homer for the A's.

Trailing 6-5, Seattle took the lead with two runs in the seventh. Carlos Guillen walked to lead off the inning advanced to second on a wild pitch and third on a groundout with two outs.

Rodriguez tied the game with an infield single off Jeff Tam. John Olerud followed with an RBI double off Mike Magnante to give Seattle the 7-6 lead.

Oakland starter Omar Olivares allowed six runs on six hits and four walks in six innings.

Seattle starter John Halama allowed four runs, two hits and six walks in four innings.

Martinez gave the Mariners a 5-0 lead in the third with his eighth home run of the season, a three-run shot off Olivares. Rodriguez also doubled home a run in the inning.

Jeremy Giambi doubled home a run in the fourth, the A's scored three runs on one hit in the fifth.

Halama gave up four walks and hit a batter to the first five hitters of the inning. Velarde and Jason Giambi each walked with the bases loaded. Ben Grieve also drove in a run with a single.

Notes: John Mabry was activated from the 15-day DL before the game. ... Catcher Joe Oliver was optioned to Triple-A Tacoma. ... Martinez extended his hitting streak to 11 games with a single in the first inning. ... Olivares has allowed three home runs in his last two starts after allowing one in his first six.