OAKLAND, Calif. -- Maybe Oakland's surprising streak against Seattle means little. The way the surging Athletics are playing, it could as easily be Tampa Bay, Texas or Toronto on the losing end of things.
"I don't care who we're playing," second baseman Mark Ellis said. "We're taking advantage of our opportunities."
Ellis homered for the second time in three games with a three-run shot as the A's matched the 1974 Atlanta Braves for the longest winning streak against a division opponent since divisional play started in 1969, according to the Elias Sports Bureau. The Braves won 15 straight versus the San Diego Padres that year.
Yet Oakland has had a longer winning streak against one opponent, getting 16 straight victories against the New York Yankees from Sept. 9, 1989, through May 1, 1991.
Haren (11-9) struck out eight and didn't walk a batter to win his fifth straight start for the first-place A's, who increased their AL West lead to a season-best 6½ games over Los Angeles after the Angels lost 9-3 at Texas. It's Oakland's biggest advantage in the division since having a seven-game lead on Sept. 30, 1992.
Oakland, 12-2 in August, won its sixth straight game and 12th in 13 and sent Seattle to its season-worst seventh consecutive defeat and 16th in a row against the division.
The Mariners are 0-7 on their 11-game road trip that resumes Thursday with the opener of a four-game series in Anaheim.
"It's a learning process," manager Mike Hargrove said. "We're getting valuable lessons. The bad part of it is we're getting our butts kicked while it's going on. We'll come out of this."
Nick Swisher, who delivered the key hits in the first two games of the series for Oakland, drew walks in his first three plate appearances and scored the first two times -- including on a balk in the fourth.
Ellis, Oakland's former leadoff hitter now batting in the No. 9 spot, connected off Gil Meche (9-8) with a drive into the left-field seats with two outs in the second for his eighth homer of the year.
Justin Duchscherer, Joe Kennedy and Huston Street completed the 10-hit shutout for the A's, who have a 10-game winning streak against Seattle in the Coliseum.
The Mariners loaded the bases against Haren with one out in the fourth but he struck out Willie Bloomquist swinging and also got Ichiro Suzuki swinging on an 87 mph splitter. The right-hander, 5-1 in seven career starts against Seattle, recorded seven straight outs beginning with Bloomquist.
"My stuff was as good as it's been all year," said Haren, helped by a sensational catch from center fielder Mark Kotsay against the wall on Suzuki's hard-hit ball in the first. "I think in order to win so many games against one team you have to catch a few breaks."
Meche, who has allowed 29 runs over his last five outings, lost his third straight start and matched his career high by dropping a fourth consecutive decision. He is winless in six starts since a victory July 14 at Toronto.
He pitched the Mariners' lone win over the A's on April 6 at Safeco Field, but was tagged for four runs and six hits in 5 1/3 innings Wednesday.
Kotsay extended his hitting streak to 15 games with a seventh-inning double, while Adrian Beltre got a hit in his 12th straight game when he singled to left in the first for Seattle.
- Frank Thomas, who has 25 homers, drew just his second intentional walk of the season.
- The A's have won six straight series. It was their ninth series sweep of the season.
- Oakland drew 34,077 for its 10th sellout of the season.
- The Mariners indefinitely moved struggling fifth starter Joel Pineiro to the bullpen and promoted left-hander Jake Woods to take Pineiro's starting spot. The switch happened a day after Pineiro allowed a career-high nine runs in an 11-2 loss to Oakland, his fifth straight defeat against the A's this season and his third loss in a row overall. He has only one victory since June 20.
- LHP Eric O'Flaherty made his major league debut in the seventh after Seattle selected his contract from Triple-A Tacoma earlier in the day. The Mariners optioned infielder Greg Dobbs to Tacoma.