BOSTON -- Jed Lowrie took his eye off a ball in the top of the 11th inning. He used his eye at the plate to win the game shortly after.
Lowrie, who dropped an easy foul pop up to extend John Buck's at-bat before he fanned to end the top of the inning, homered into the Red Sox bullpen off Casey Janssen (4-2) for his first career game-ending homer.
"I don't think I've faced him before that I can remember. I wanted to watch him throw a few so I could see him," Lowrie said. "He hung a 2-2 curveball and I hit it out."
The victory came after an embarrassing, season-worst 16-2 loss to the Blue Jays on Friday.
"A walk-off can certainly get us on a roll," said Boston reliever Daniel Bard, who worked two scoreless innings.
Boston catcher Victor Martinez drove in three runs to go along with a solid defensive play on a jarring collision. He held onto a relay throw as Lyle Overbay knocked him over for the final out of the fourth.
Former Blue Jays player Marco Scutaro had a double, two singles and scored a pair of runs.
Overbay had a game-tying, two-run homer for Toronto after going 4 for 5 with a career-best seven RBIs in Friday's win.
"The bullpen came in and did a good job," Toronto manager Cito Gaston said. "Of course, the last pitch looked like a hanging breaking ball. That'll get you beat sometimes."
The Red Sox improved to 10-4 against Toronto this season. They have won seven times in games decided by two runs or less.
It was Boston's first game-ending homer since David Ortiz hit one against the White Sox last Aug. 26.
"Curveball. I hung it," Janssen said. "He's a good hitter and he hit my mistake."
Jonathan Papelbon (5-5) pitched a perfect inning for the win.
Mike Lowell reached second to open the eighth when his short pop down the left-field line ticked off shortstop Yunel Escobar's glove, bounced onto the track and into the stands for a ground-rule error, but Boston failed to score.
Toronto tied it at 4 in the sixth against starter Daisuke Matsuzaka when John Buck had a sacrifice fly and Overbay hit a two-run homer into the right-field bleachers after being pitched around his first two at-bats with an intentional walk and a walk with first open. But, this time, with a runner on second and first open again, Overbay belted the second pitch over the Blue Jays' bullpen.
"We tried to get him to chase something there, but Dice was pretty good," Boston manager Terry Francona said.
Martinez's two-run single gave Boston a 2-0 lead against starter Ricky Romero.
The Blue Jays closed to 2-1 in the fourth on John McDonald's RBI double, but Overbay was cut down when he barreled over Martinez, who caught second baseman Yamaico Navarro's throw from shallow center field. Martinez got up, smiled and playfully retagged Overbay on the chest.
Martinez and Adrian Beltre each had RBI singles in the fifth.
Romero pitched seven innings, giving up four runs, nine hits, striking out eight and walking one. He entered with a 1-4 record and career-worst 8.51 ERA against the Red Sox.
Matsuzaka gave up six hits and four runs -- three of each coming in the sixth -- in eight innings, walking three and fanning eight.
Gaston talked before the game about how Matsuzaka's hesitation windeup "really messes with your timing." The right-hander seemed to have the Blue Jays hitters off-balance a lot early, holding them to three hits and number of weak swings in the first five innings.
Boston has won seven times in its last at-bat at home this season, most since nine in 2006. ... Red Sox C Jason Varitek, sidelined since July 1 with a broken right foot, took early BP. Francona said the team had a conference call to discuss the injury "[the doctor] doesn't feel Jason can hurt the foot even if he feels some discomfort, but he's not ready to play yet." ... LHP Hideki Okajima, on the 15-day DL with a strained right hamstring since August 6, threw one scoreless inning of relief in a rehab appearance for Triple-A Pawtucket, allowing one single. ... Toronto 3B Edwin Encarnacion, who missed Friday's game with a sore left wrist, took BP and Gaston said he may play Sunday. ... Navarro made his first start at second. ... Boston C Jarrod Saltalamacchia is expected to remain hospitalized until Monday to treat an infection in his right lower leg.