Nate McLouth added three hits and led off the game with a homer while Mark Reynolds contributed a pair of RBI hits for the Orioles, who pulled to within one-half game of the American League East-leading New York Yankees with the win.
Adam Jones went 3-for-4 with four runs scored and Manny Machado chipped in with two hits, including an RBI single to cap a three-run first inning.
Chris Tillman (8-2) held the Mariners to one run on three hits over six innings, walking none and striking out four as the O's took the opener of a three-game set.
Mariners starter Hector Noesi (2-12) was rocked for seven runs (six earned) on eight hits over 1 1/3 frames.
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