BOSTON - The Twins were down to their final strike Saturday, lamenting a night of missed chances at Fenway Park, when Joe Mauer changed everything with one swing.

Red Sox closer Alfredo Aceves threw a 95-miles-per-hour fastball over the plate, and Mauer drove it over the Green Monster for a three-run homer, giving the Twins a 6-4 victory.

It was the kind of opposite-field smash the Twins have seen Mauer hit many times before, a ball that has turned into an out many times at the more spacious Target Field. But at Fenway, it landed just beyond that famous wall.

"I think that's why Boston would really like to have Joe Mauer here, probably," Twins manager Ron Gardenhire said. "This wall would probably work out pretty well for him. But fortunately for us, Joe Mauer is a Minnesota Twin, and he's going to be one for a long, long time."

Mauer's $184 million contract doesn't expire until 2018, and Twins fans have big expectations for him to produce moments just like this. It was his seventh homer of the season, and it gave the Twins three victories in the same series at Fenway for the first time since 1994.

The Twins trailed for most of Saturday's game, as Clay Buchholz held them to one run over seven innings. But they tied it 2-2 in the eighth inning on a sacrifice fly by Justin Morneau off Aceves. The Twins missed a chance to take the lead that inning after loading the bases with no outs.

Glen Perkins relieved Cole De Vries, who pitched seven strong innings, and Pedro Ciriaco led off Boston's eighth with a pinch-hit home run over the Monster. It was Ciriaco's first career home run and just the fifth given up this season by Perkins.

The Red Sox added an insurance run that inning, but trailing 4-2, the Twins weren't finished. Jamey Carroll hit an RBI single, trimming the lead to 4-3, and Ben Revere singled. A wild pitch moved the runners to second and third for Mauer.

Two days earlier, Gardenhire kept Mauer out of the lineup for the first time since June 22, saying it looked like Mauer could use a rest. But Mauer said he used that day to take extra swings in the batting cage.

"It's the time of year when the bat feels heavy, and sometimes when that happens, you try to do too much and your swing can get long," said Mauer, who was riding a 1-for-14 skid entering the Boston series. "[Against Aceves] I was just trying to stay short and hit the ball hard. I got one up and over the plate, and I was able to go with it."

Like any great Mauer at-bat, part of the story was the pitches he didn't swing at. With a 2-2 count, Aceves threw a fastball just inches off the outside corner. Mauer took it, and plate umpire David Rackley called it a ball as Aceves looked away in disgust.

"I think I started laughing in the dugout," Gardenhire said. "There's not too many people that can take that pitch, and not too many people who have that much courage, but Joe can. He knows the strike zone as well as anybody; that's why he's won all those batting titles. Most of us might have been sitting back in the dugout."