BOSTON (AP) -- Dustin Ackley had three hits and scored three runs, Seattle's bullpen was sharp for the second straight day and the Mariners beat Boston, 8-6, on Sunday for the Red Sox's eighth straight loss.
Ackley had a triple, double and single, finishing 13 for 25 in six games against Boston this season. The Mariners completed their first-ever sweep in a series of three or more games in Fenway Park.
Kyle Seager drove in two runs for Seattle.
Dominic Leone (7-2) worked 2 2-3 innings of hitless relief for the win. Fernando Rodney escaped a bases-loaded jam in the ninth for his 38th save and the Mariners' pen held Boston to one run over 6 2-3.
In Saturday's victory, Seattle's relievers gave up just two hits in 5 1-3 innings of scoreless work.
Will Middebrooks had a two-run double and drove in three runs for Boston, which is on its worst stretch since losing 10 straight in May.
Trailing 5-3, Seattle scored a run in the fourth and took the lead with two in the fifth against Allen Webster (3-2). Ackley tied it with his triple. He scored the go-ahead run on a sacrifice fly.
Middlebrooks' two-run double had given Boston a 5-3 lead in the third and chased starter Hisashi Iwakuma, who gave up five runs on six hits over 2 1-3 innings, his shortest start of the season. He also hit consecutive batters in the first.
Iwakuma entered with a 17 2-3 innings scoreless streak, but that ended four batters into the first.
Webster was tagged for six runs on eight hits in 4 1-3 innings.
Both teams scored three runs in a first inning that lasted 42 minutes. Kendrys Morales, Seager and Logan Morrison each had RBI singles for the Mariners. Middlebrooks had a two-run double and Yoenis Cespedes an RBI single.