In the storied history of the franchise, the 14 runs were the most ever given up by the Yankees in a playoff game.
After losing the first two games of the series at home following a regular season in which they equaled the major league record with 116 victories, the Mariners finally put their offense in gear with 15 hits and also benefited from some shoddy New York fielding.
The victory came after manager Lou Piniella said his Mariners would bring the series back to Seattle, something that would require two victories in the three games scheduled at Yankee Stadium.
Having reduced their deficit in the series to 2-1, Seattle will try to even it up Sunday night when the Mariners send Paul Abbott to the mound to oppose Roger Clemens.
The three-time defending champion Yankees appeared on their way to another victory Saturday when Bernie Williams hit a two-run homer in the first inning to stake Orlando Hernandez to the lead. Hernandez came into the game with a 7-0 career playoff record.
But after Williams hit his homer, Seattle starter Jamie Moyer retired 13 batters in a row -- one of the outs coming when left fielder Stan Javier leaped to take a home run away from Alfonso Soriano to lead off the third.
It began to unravel for the Yankees in the fifth, when Seattle tied the game at 2-2.
Tom Lampkin singled with one out, but the Yankees were unable to turn an inning-ending double play on a grounder back to Hernandez. The New York starter than walked Ichiro Suzuki and McLemore before Boone, who led the league with 141 RBI this season, drove in two runs with a liner that diving left fielder Chuck Knoblauch had in his glove for an instant but which was ruled a single.
Seattle then sent 11 batters to the plate in the sixth inning, producing a single, double, triple and two homers while capitalizing on a fielding error by reliever Mike Stanton.
John Olerud started the inning by putting the Mariners in front with a homer off the right-field foul pole.
Javier followed with a single, stole second and Mike Cameron walked. Stanton then came in to relieve Hernandez and pinch-hitter Dan Wilson laid down a bunt on the left side. Stanton got to the ball and tried to get Javier at third, but the throw sailed past third baseman Scott Brosius. Javier came in to score on the error and runners wound up at second and third.
Suzuki was intentionally walked to load the bases and McLemore cleared them with a rocket to left-center that rolled all the way to the wall for a triple.
Mark Wohlers relieved Stanton and promptly gave up an enormous home run to center by Boone that made it 9-2.
The Mariners added two runs in the seventh with another error figuring in the scoring. Cameron walked to lead off the inning, after which Wohlers grabbed a bouncer off the bat of Wilson and threw it into center field. Cameron scored on a base hit by David Bell and, two outs later, Wilson came in on another single by Boone.
Bell singled in a run in the eighth and Seattle added two in the ninth on Jay Buhner's homer and Olerud's RBI single.
Despite the New York fielding problems, only three of the Seattle runs were unearned.
The offensive outburst took the spotlight off Moyer, who won 20 games during the regular season and was the winning pitcher in both Game 2 and Game 5 in the division series comeback against Cleveland.
Moyer allowed the two runs on four hits with one walk and five strickouts in seven innings. Jose Paniagua allowed a run in the eighth and John Halama pitched a perfect ninth for the Mariners.