DETROIT -- Mike Napoli's majestic homer began the early breakthrough Boston needed.
Now, the Red Sox are a win away from the World Series -- with a bullpen that Miguel Cabrera and the Detroit Tigers still can't seem to solve.
Napoli opened the scoring with another big long ball, Junichi Tazawa again bested Cabrera in a crucial spot and the Red Sox edged Detroit 4-3 on Thursday night.
Boston returns to Fenway Park with a 3-2 lead in the AL championship series. Game 6 is Saturday with the Tigers' Max Scherzer facing the Red Sox's Clay Buchholz.
"Our guys are well aware of where we are," manager John Farrell said. "But at the same time the beauty of them is to not get ahead of themselves, and that will be the case once that first pitch is thrown on Saturday."
Cabrera was thrown out at the plate in the first inning, halting an early Detroit rally, and he hit into a double play against Tazawa with runners at the corners in the seventh. The Tigers scored a run on the grounder, but it was a trade-off the Red Sox were willing to make.
Napoli led off a three-run second with a drive off Anibal Sanchez into the ivy beyond the wall in center field.
Detroit's starters had allowed only three runs in 27 innings through the first four games of the series. After pitching six no-hit innings in Game 1, Sanchez allowed four -- three earned -- in six innings Thursday.
Jon Lester allowed two runs and seven hits in 5 1-3 innings. He walked three and struck out three, and the Boston bullpen held on to finish off the fourth game of the series to be decided by one run.
"There's probably a reason I don't have any hair," Red Sox second baseman Dustin Pedroia said. "It's stressful."
Down 4-2 in the seventh, the Tigers put runners on first and third with nobody out when Jose Iglesias and Torii Hunter singled. Cabrera, who struck out with runners at the corners against Tazawa in the eighth inning of a 1-0 loss in Game 3, hit a soft grounder to second for a double play this time.
That was Detroit's last stand in this one. Craig Breslow retired slumping Prince Fielder to end the seventh and got the first out of the eighth. Then Koji Uehara retired five straight for the save.
Now Detroit turns to Scherzer, a 21-game winner, to try to extend the season. The Tigers will have Justin Verlander ready to pitch Game 7 if there is one.
Detroit may be without catcher Alex Avila in Boston. He left after the top of the fourth with a strained left knee.
Boston led in only four of 36 innings in the first four games, but the Red Sox won two of them. They struck early in Game 5 when Napoli's drive easily cleared the 420-foot marker in center and landed in the ivy above two rows of bushes. That was the start of a three-run second inning, and it was Napoli's second homer of the series. His solo shot accounted for the only run of Game 3.
Detroit revamped its lineup before its Game 4 win -- dropping Austin Jackson from the leadoff spot to eighth and moving almost everyone else up a place. The Tigers went with that same general framework Thursday, but it was Boston manager John Farrell's adjustments that paid off.
After Napoli's homer, Jonny Gomes -- starting in left field instead of Daniel Nava -- reached on an error by Cabrera at third base. One out later, 21-year-old Xander Bogaerts -- he started at third instead of Will Middlebrooks -- hit a double.
David Ross, catching in place of Jarrod Saltalamacchia, doubled with men on second and third. Only one run scored on the play because Bogaerts didn't get a good jump from second, but he came home anyway when Sanchez couldn't handle Jacoby Ellsbury's line drive back to the mound. It went off Sanchez's glove for an infield single and a 3-0 lead.
Boston missed out on another run that inning when Ross was thrown out at home on Shane Victorino's grounder. Ross plowed through Avila at the plate -- then gave Avila a pat on the backside after he held onto the ball.
Ross and Avila have both dealt with concussion problems this year, and Avila was later hit in the mask by a foul ball.
In the third, shortstop Jose Iglesias gave the Detroit fans something to cheer about with a terrific catch on a shallow flyball by David Ortiz. Iglesias, who was shifted over to the right of second base, ran all the way out to short left field, finally catching the ball with a quick snatch of his glove hand.
But Napoli followed with a double, went to third on a groundout and scored on a two-out, two-strike wild pitch by Sanchez to make it 4-0.
Sanchez allowed nine hits and struck out five.
Lester worked in and out of trouble. He was helped in the first inning when Cabrera was thrown out at home for the third out. Cabrera has been slowed by a number of injuries over the last couple months, and when Jhonny Peralta singled to left, it appeared the Tigers would have the bases loaded with two outs and Omar Infante batting.
But coach Tom Brookens started waiving Cabrera around third, and when Brookens changed course and put up the stop sign, the Detroit slugger ran through it and was out at home on a play that wasn't close.
The Tigers had two on and one out in the fourth when Brayan Pena pinch-hit for the injured Avila. Pena hit a grounder to the pitcher, and the Red Sox turned a double play with a nifty catch-and-relay at second by shortstop Stephen Drew.
Cabrera managed an RBI single in the fifth. With two on and one out in the sixth, the Red Sox pulled Lester, bringing in Tazawa. Pena immediately singled home a run, but Jackson hit into an inning-ending double play.
NOTES: At 21 years and 16 days old, Bogaerts became the youngest Red Sox player to start a postseason game. The previous record holder was Babe Ruth, who was the starting pitcher at 21 years and 246 days old in Game 2 of the 1916 World Series. ... Thursday's game was played under a misty rain at times, but was never delayed. ... There was an odd play in the Boston ninth when Middlebrooks, in the game as a pinch-runner, went from first to third on a sacrifice bunt by Ross. Cabrera came charging in to field the bunt, and Pena was slow to get to third and cover the base. Pena caught Fielder's throw on the foul side of third base and, when he spun to attempt a tag, he first made contact with umpire Rob Drake, who was very close to the bag.