Chris Young, who moved to the American League from Arizona in the off-season, smacked a solo homer as well in is Athletics debut to help Oakland avoid its first 0-3 start since 1995.
The A's rapped out 11 hits after managing just six in their first two games.
Tommy Milone (1-0) went seven innings, striking out four while giving up two runs on four hits.
Mariners starter Joe Saunders (0-1) got through only four innings, getting dinged for four runs on seven hits and four walks.
Nate Freiman got one run back for Oakland with an RBI single up the middle in the second and Yoenis Cespedes' sacrifice fly to center in the third tied it up.
Lowrie then hit a two-run, two-out double in the fourth, and then he and Young nailed back-to-back solo shots in the seventh for the final margin.