The Red Sox answered every time the Mariners put a rally together, possibly aided by their large turnout of fans at the game. But Sexson answered for good in the sixth, lining his two-run shot over the right-field wall.
Despite starting the season in a slump, Sexson is now hitting .344 with five home runs and eight RBIs in his last nine games, although it's no surprise to manager Mike Hargrove, who had continually defended Sexson during his slump.
"I think if you give guys enough at-bats and enough opportunities, their track record says that they're going to do it eventually," Hargrove said. "You have to wait through the bad to get to the good, because when it's good, it's awfully, awfully good."
Sexson's blast put the Mariners up, 8-6, and the bullpen did the rest. Eric O'Flaherty, Brandon Morrow, George Sherrill and J.J. Putz combined for the final 3 1/3 innings, allowing one run on three hits while striking out six.
The Red Sox had no answer for Seattle's relievers.
"That's the reason they're pitching in the late innings," Hargrove said. "If you can get the right match, then they have the ability to do that."
None proved that point more than Sherrill, who came up big by striking out Red Sox slugger David Ortiz with two on and none out in the eighth.
"I went to see if I could put him away, and not leave anything over the plate, so he could just flip it into the outfield," Sherrill said. "I think it's a good win for us, a big win for us."
Putz struck out the side in the ninth for his 22nd save in as many chances, and his 68th career save, passing Norm Charlton for third on the Mariners' all-time saves list.
They haven't always been easy, but he's sure made it look that way. Putz retired the final five batters in order, and struck out pinch-hitter Manny Ramirez to end the game.
"It's never a pleasant sight to look into the on-deck circle and see him just sitting there waiting for you," Putz said. "So I was able to get ahead of him and get him to chase some pitches."
And so goes the story of the Mariners' bullpen thus far -- record crucial outs when it's needed most. Even when its ace, Hernandez, doesn't have his best stuff.
"I think we've been pretty good all season," Morrow said. "I think we've got a lot of good arms in the back of the bullpen, and George has just shut down lefties all season. O'Flaherty's been pretty good, I think I've been pretty good and J.J. has been outstanding."
O'Flaherty earned the win for the Mariners, improving his record to 5-0 in his Major League career, joining Julio Mateo as the only Mariners pitchers to begin their big-league careers 5-0.
The bullpen, though, has shown its skipper resilience, ability and dedication.
The closer has shown Hargrove even more.
"Putz is better than [Jose] Mesa, I think," Hargrove said, comparing his current closer to his closer in Cleveland. "That's not a knock against Jose. Jose saved 46 games for me in '95, and 36 games in '96. That's a lot of games, and he was awfully good. But J.J. is pretty good."
Willie Bloomquist was 2-for-3 with two RBIs and a home run, his second of the season and first at Safeco Field since July 13, 2003, a span of 451 at-bats.
And as their hitting, pitching and swagger continue to click, the Mariners hope this series win is a statement to the rest of the big leagues.
"We want to play well against the best," Sexson said. "We kind of showed what we're made of."