It wasn't the best outing for former Oregon State pitcher Sam Gaviglio on Thursday.
Oakland jumped on him for three runs in the first inning and added four more in the fifth inning as the Athletics beat Gaviglio and the Seattle Mariners 7-4 Thursday at Safeco Field.
It was the eighth consecutive home loss for the Mariners (41-46).
Mitch Haniger hit a solo homer in the fifth inning and Danny Valencia a three-run homer in the bottom of the ninth inning for the Seattle runs.
Yonder Alonso had an RBI double and Jed Lowrie a two-run double in the first inning off Gaviglio (3-4).
Khris Davis hit a three-run homer and Bruce Maxwell a solo homer in the fifth inning off Gaviglio, who gave up nine hits and seven earned runs.
Paul Blackburn scattered eight hits and gave up one run in 7 2/3 innings for the win.
Jean Segura went 4-for-4, raising his average to .354. Yovani Gallardo allowed only one hit in 4 1/3 innings in relief.
Oakland moved to 38-48.
The second of the four-game series will be 7 p.m. Friday, with James Paxton (6-3, 3.27) pitching for Seattle opposite Sean Manaea (7-4, 3.75).