Despite a shaky performance from starter Erasmo Ramirez, the Mariners matched their longest winning streak of the season thanks to another offensive outburst. One night after putting up 12 runs on the Red Sox, Seattle hit two homers and handed Boston its fifth loss in six games.
Seager's homer was his 11th of the season, 10 of those coming at Safeco Field. Mike Zunino followed with a solo shot as part of Seattle's four-run fifth inning. It was Zunino's 10th home run.
Joe Beimel (2-1) got four outs in relief of Ramirez to get the victory. Ramirez again failed to get deep into the game and was done after 4 1-3 innings.
The victory was Seattle's 15th in June and secured consecutive winning months for the first time since 2012. The Mariners (42-36) are six games over .500 for the first time this season.
Seattle has mostly been winning with pitching but the bats have shown up against the Red Sox. Logan Morrison had the big blows in the series opener with two home runs. It was Seager's turn on Tuesday.
Seager's double in the first scored Endy Chavez and Morrison followed with a sacrifice fly for an early 2-0 lead. Chavez tripled for the second straight night in the second inning to score Brad Miller for a 3-0 lead.
It was Seager's turn again in the fifth. Robinson Cano's single with one out put runners on the corners and Seager turned on an inside pitch from Peavy just inside the right-field foul pole and off the windows of the cafe in the outfield. Seager was barely back in the dugout when Zunino lined his homer into the Mariners bullpen, nearly hitting reliever Danny Farquhar for a 7-2 lead.
Peavy (1-6) has allowed 16 homers in 16 starts this season. He was pulled after the fifth and the seven earned runs were a season high. Peavey has lost six straight decisions, his only win this season coming on April 25 against Toronto. In the 11 starts since his victory, Peavy has left the mound with the lead only once.
Control was again the problem for Ramirez. He ran his scoreless innings streak to 19 1-3 before giving up a two-run homer to Brock Holt in the fourth inning. But it was five walks and a number of long at-bats that ended his night early. While not giving up many runs, Ramirez pitched more than five innings only once in his past five starts.
NOTES: Beimel was the first of four relievers used by Seattle. ... Boston RHP Clay Buchholz (knee) will come off the 15-day DL to start Wednesday's series finale. Buchholz last pitched for the Red Sox in late May. ... Ramirez's scoreless innings streak is the longest for any Seattle pitcher this season.