J.J. Hardy, Chris Davis, Mark Reynolds, Manny Machado and Robert Andino all drove in runs as the Orioles avoided a three-game sweep and stayed one game behind the American League East-leading New York Yankees.
Jim Johnson was called in to collect his 43rd save after the A's scored a run in the ninth.
The loss went to Daniel Straily (2-1), who surrendered four runs on five hits over 4 2/3 frames as AL wild card-leading Oakland lost for just the seventh time in 30 games.
Josh Reddick smacked a two-run homer, driving in three runs in all, and Stephen Drew also delivered a two-run shot for the A's.
2014: The Year in Music [PHOTOS]