BOSTON -- The Seattle Mariners put at least the first two runners on base in each of the first three innings against Boston right-hander Rick Porcello but could only scratch out two runs. That ineffectiveness came back to haunt them as the Red Sox waited out Mariners starter Adrian Sampson and scored four runs in the fourth and fifth innings on the way to a 6-2 win Saturday afternoon at Fenway Park.

Seattle's Leonys Martin, Seth Smith and Robinson Cano opened the game with consecutive singles before Nelson Cruz grounded into a run-scoring double play in the first inning. Adam Lind led off the second with his ninth home run of the season.

But that was all the damage the Mariners could do as Red Sox right-hander Rick Porcello settled into a groove.

"I felt like I had a better feel as the game went along," Porcello said. "Next thing I knew it was bases loaded and nobody out (in the first). As the game progressed, I was able to get a better feel for it."

At one point, Porcello retired eight straight batters before Smith, who went 3-for-3, reached on a two-out bunt in the fifth. Porcello then retired the next four batters before giving way to Junichi Tazawa for the seventh.

"I thought the key to this game was to limit to single runs in the first and second," Red Sox manager John Farrell said. "He gets a key double play of Cruz in the first."

Porcello went six innings, giving up two runs and eight hits with no walks, six strikeouts and a home run. He improved to 8-2 with a 3.76 ERA.

"You got to give credit to Porcello," Mariners manager Scott Servais said. "He had some pitches and he elevated some fastballs, got it by our guys in spots he needed to do it. So you got to give him a little bit of credit. But we have struggled recently in those men on third, less than two-out situations. We got to be a little more proficient at that. The big parts of the game you got to add on. That has hurt us the last week or 10 days."

Sampson (0-1), making his major-league debut, had retired eight straight batters before Jackie Bradley Jr.'s two-out solo home run in the fourth, his 12th homer of the season, got Boston on the scoreboard.

"He hung in there," Servais said. "He probably wasn't as sharp as he normally is but it's his major-league debut, there's going to be a lot of butterflies. But I thought he hung in there, gave us a chance and we were kind of in the game there. We had opportunities to score a few more runs early and just didn't get it done."

In the fifth, No. 8 hitter Chris Young, Christian Vazquez and Mookie Betts opened with consecutive singles to produce one run. After Dustin Pedroia grounded into a run-scoring double play, Xander Bogaerts launched his ninth home run of the season, giving Boston a 4-2 lead and ending Sampson's outing with left-hander Mike Montgomery replacing him.

"This is a special place to start a professional career," Sampson said. "After the first inning I settled in pretty good. I think toward the end of the game I had some bad misses and kind of let the ball get going on me. But it was good. I felt really good about it."

The Red Sox got a run off Montgomery in the fifth when Vazquez's two-out double scored Hanley Ramirez.

Boston added one run in the eighth when Ramirez led off with a double. On Bradley's lineout, Cano attempted to double off Ramirez at second, but shortstop Ketel Marte missed the throw, allowing Ramirez to score.

Every batter in the Red Sox lineup had at least one hit except for Pedroia, who went 0-for-4 and grounded into two double plays.

Craig Kimbrel threw a perfect ninth for his 16th save of the season.

NOTES: Each team made several roster moves. The Red Sox called up INF Deven Marrero and OF Ryan LaMarre. OF Rusney Castillo and LHP Roenis Elias were optioned to Triple-A Pawtucket after Friday's game. ... The Mariners called up LHP Adrian Sampson, who started the game and made his major-league debut. LHP David Rollins was optioned to Triple-A Tacoma after Friday's game. ... RHP Taijuan Walker is expected to start the series finale for Seattle on Sunday. Walker left his Tuesday start at Tampa Bay because of a foot injury after only 3 2/3 innings. ... Red Sox C Ryan Hanigan, who has been on the disabled list since June 5 because of a neck strain, continues to work his way back. He has been taking batting practice and caught a bullpen session on Saturday. He is expected to throw to bases on Monday.