Oakland scored three runs in the first inning and McCarthy (6-3) went seven dominant innings for his sixth consecutive victory.
McCarthy struck out five and allowed one walk before turning the game over to Grant Balfour and Ryan Cook who held Los Angeles hitless the rest of the way.
Aaron Harang (5-4) took the loss after allowing three runs on three hits, while throwing 105 pitches in just 3 2/3 innings. Harang struck out six but allowed a career-high eight walks.
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