BOSTON -- When Max Kepler squared up a sixth-inning fastball from Boston's Rick Porcello, it almost looked as if he were swinging a golf club instead of a baseball bat.

Kepler smacked a 409-foot, two-run blast off the struggling Red Sox ace, and he finished with three RBIs on the night to lead the Minnesota Twins to a 4-1 win on Wednesday night at Fenway Park.

"He hits 1-irons out of the ballpark," Twins right fielder Robbie Grossman said of Kepler's power swing. "It's pretty special the kind of juice that he creates."

Kepler's big night was supplemented by a strong outing from starter Adalberto Mejia (3-3), who tossed 5 2/3 scoreless innings, allowing five hits and a walk while striking out three.

The 24-year-old left-hander has not given up a run in 10 2/3 innings over his past two starts.

"Similarly to his last start, he kept walking off the field with zeros," Twins manager Paul Molitor said. "We needed a little bit of a pick-me-up from our starter, and he was able to provide that."

Miguel Sano also drove in his team-leading 53rd run of the season for Minnesota (40-36), which was outscored 13-3 in losing the first two contests of the four-game series.

Xander Bogaerts drove in the lone run for Boston (43-35), which went 0-for-10 with runners in scoring position and had its modest two-game winning streak snapped.

"Whether it was a breaking ball off the plate or down low in the zone, we did chase a little more tonight than we have in other ballgames," Boston manager John Farrell said.

Porcello (4-10) failed in a bid to win back-to-back games for the first time this season, giving up four runs on six hits and two walks with six strikeouts in six frames.

"Six innings, four runs. It's not like they're beating the cover off the ball," Porcello said. "It's just a couple things here and there that I got to clean up.

"I'm not making excuses for myself. I definitely hold myself accountable for the loss tonight. But in the grand scheme of things, got to keep building off of what I'm doing and what we're doing."

Porcello retired the game's first two batters before Joe Mauer doubled and Sano brought him in with an RBI double. Kepler's ensuing RBI single gave Minnesota a 2-0 lead.

With one on and no outs in the sixth, Kepler doubled the lead with his line-drive homer off an 0-1 fastball from Porcello that sailed into the Boston bullpen in right field.

"On a night where we're scuffling to get anything going offensively, that's unfortunately looking like a big lead -- a 4-0 lead," Farrell said.

Boston brought the tying run to the plate with one away in the seventh as Dustin Pedroia walked to load the bases for Bogaerts, whose groundout to short scored a run.

Mitch Moreland struck out swinging to end the threat.

Mookie Betts doubled with one out in the ninth against Twins closer Brandon Kintzler, but Pedroia grounded out and Bogaerts struck out swinging to lock up Kintzler's 21st save.

With the Indians' 5-3 win over the Texas Rangers, the Twins remain a half-game behind Cleveland for first place in the American League Central.

NOTES: Boston DH Hanley Ramirez (left knee soreness) was not in the lineup for a third straight game. "I think the second half (of the season) is coming and I'm ready for that," Ramirez told MLB.com. ... Red Sox manager John Farrell returned to the dugout after serving a one-game suspension for arguing a balk call and making contact with crew chief Bill Miller on Saturday. Farrell was also fined an undisclosed amount. ... Minnesota placed LHP Craig Breslow (thoracic rib soreness) on the 10-day disabled list. Breslow (1-1, 5.28 ERA) had not been on the DL since 2013, and he told the St. Paul Pioneer Press it "wouldn't be fair" to the team to try to pitch through the injury. ... The Twins also activated RHP Phil Hughes, who had been sidelined with right arm soreness, from the DL. ... Twins RHP Kyle Gibson (4-5, 6.23 ERA) opposes Red Sox LHP David Price (2-2, 4.76 ERA) in the series finale Thursday.