The Oakland Athletics clinched their third consecutive trip to the postseason Friday night, riding Matt Olson's three-run homer and right-hander Chris Bassitt's strong pitching to a 6-0 victory over the visiting San Francisco Giants in the opener of a three-game series.
The win, coupled with third-place Seattle's loss to San Diego, assured the American League West-leading A's (32-19) will finish no worse than second in the division.
The top two teams in each division are guaranteed playoff berths this season.
The A's, who made the playoffs as a wild-card team each of the last two seasons, also lowered their magic number to win their first division title since 2013 to three over second-place Houston.
The Giants (25-25), meanwhile, saw a two-game winning streak come to an end and fell into a tie with St. Louis and Cincinnati for the second wild-card spot in the National League.
Olson's homer came in the third inning after the A's had taken a 1-0 lead off Giants starter Logan Webb (2-4) in the first on a Jake Lamb RBI single.
A single by Tommy La Stella and walk to Mark Canha set the stage for Olson in the third, and he deposited his 14th homer of the season into the right-field bleachers for a 4-0 lead.
The A's completed their scoring, and ended Webb's night in the fourth, with La Stella and Marcus Semien driving in runs with consecutive singles for a 6-0 advantage.
Webb was pulled at that point, charged with six runs on six hits in 3 1/3 innings. He walked two and struck out one.
Bassitt (5-2) took a shutout two outs into the seventh before exiting in favor of right-hander Yusmeiro Petit with two on and two out. Petit got Mauricio Dubon to fly out to end the threat.
J.B. Wendelken and Jordan Weems pitched hitless eighth and ninth innings, respectively, to complete Oakland's fourth shutout of the season.
Bassitt gave up three hits and three walks in his 6 2/3 innings. He struck out seven.
La Stella had two hits and Semien scored twice for the A's, who swept a three-game series in San Francisco last month.
Brandon Crawford had the Giants' only extra-base hit of the game, a double.
--Field Level Media