Athletics 2, Angels 1: Josh Donaldson delivered a two-out single with the bases loaded in the ninth inning for his third walk-off hit of the season as host Oakland reduced its magic number for clinching the American League West to six.
Donaldson finished with three hits and Brandon Moss went 2-for-4 with an RBI for the Athletics, who maintained their 6 1/2-game division lead over Texas with 11 contests remaining.
Former Angel Alberto Callaspo led off the ninth with a single off Michael Kohn (1-3) and pinch runner Jemile Weeks advanced to second on Stephen Vogt's flyout. Kohn walked the next two batters to load the bases and struck out Daric Barton before Donaldson lined an 0-2 pitch into center field to plate Weeks with the winning run.
Grant Balfour (1-3) earned the victory after striking out the side in the top of the ninth.
The Angels grabbed an early lead as Mike Trout launched a two-out solo homer off Sonny Gray in the first inning. Oakland answered in the bottom half with a ground-rule double by Moss that plated Coco Crisp, who drew a leadoff walk from Garrett Richards.
GAME NOTEBOOK: Richards allowed one run and seven hits in seven innings, while Gray yielded one run and five hits over six frames. ... Oakland has won six of its last seven games and 17 of 22. ... Erick Aybar recorded two hits for the Angels, who fell to 6-3 on their 10-game road trip.