"I've said from day one that I know we can play with them," Manager Art Howe said Thursday after the A's defeated the Mariners, 6-3, at Seattle.
Eric Chavez singled in the tiebreaking run in the eighth inning as the A's handed the Mariners their second consecutive series loss for the first time this season.
"We've played them tough the last couple of series," Howe said. "Now, we have to keep it up the rest of the way and play everybody the way we play them."
The defending American League West champion A's, in third place in the division 19 games behind Seattle, are 5-8 against the Mariners. But the A's have won four of the last seven.
The Mariners lost their second game in a row for the sixth time this season and the third time in June. Seattle is 19-4-2 in series.
At 56-21, the Mariners have the best record in baseball, but they've dropped six of nine.
"We've got some margin in here and we're using it," Mariner Manager Lou Piniella said.
Tampa Bay 4, Boston 3--Bryce Florie returned to the major leagues for the first time since a line drive shattered his face last September, but the Red Sox lost at Boston.
Pinch-hitter Russ Johnson drove in the tiebreaking run with a ninth-inning infield hit to help the Devil Rays gain a four-game split. The Red Sox had won 11 in a row over the Devil Rays before losing Wednesday night.
The Red Sox, who placed Pedro Martinez on the disabled list a night earlier because of a sore right shoulder, lost another starting pitcher when Frank Castillo came out in the second inning because of a strained muscle on his right side.
Florie relieved and gave up one run and two hits in 2 1/3 innings. In his previous appearance, last Sept. 8, a liner by the New York Yankees' Ryan Thompson fractured several bones in his face and left vision in his right eye impaired.
Kansas City 9, Detroit 2--Mike Sweeney had a home run and two doubles, increasing his league-leading extra-base hits total to 50 and helping the Royals complete a three-game sweep at Kansas City, Mo.
Sweeney, three for four with four runs batted in, hit a two-run homer into the left-field water fountains in the seventh. Two batters later, Jermaine Dye homered to chase Jeff Weaver (6-8), who gave up seven runs and 11 hits in 6 1/3 innings.
Wells, also forced out in the first inning of his June 8 start against the Chicago Cubs, departed after his warmup pitches before the bottom of the third.
Lowe (3-0) struck out four and walked three in four hitless innings.
Baltimore 5, Toronto 0--Sidney Ponson pitched a two-hitter at Toronto for his first shutout in more than a year.
Ponson (5-5), who retired 16 consecutive batters starting in the second inning, struck out six and walked one. His only other shutout was a four-hitter against the Twins on April 16, 2000.