Boston's hopes of turning a dismal season around took a big hit against the Blue Jays.
Marcus Stroman and two relievers combined on a one-hitter, Juan Francisco drove in four runs and came within a double of the cycle and Toronto beat the Red Sox 8-0 on Thursday, last-place Boston's third straight loss.
"We were behind the eight-ball right from the first or second inning, and were never really in this one," Red Sox manager John Farrell said.
Boston set season-highs in runs, hits (18) and home runs (four) in Monday's 14-1 rout, their fifth straight win and eighth in nine games, but managed just seven runs over the final 27 innings of the series.
The one-hitter was Toronto's first against the Red Sox in 550 all-time meetings. Boston was shut out for the 10th time this season.
Slugger David Ortiz felt back spasms on a check swing in the ninth and was replaced by Jonny Gomes, who flied out to end the game.
"Hopefully it's not anything serious," Ortiz said.
Stroman's no-hit bid ended when Shane Victorino blooped a single to center to lead off the seventh. One out later, Victorino was erased on Mike Napoli's double-play grounder.
Stroman (6-2) only allowed two other baserunners on walks and matched a season-high by striking out seven in seven innings. The rookie right-hander is 5-1 with an 1.54 ERA in seven home starts.
"He's pitching like a veteran who's been around a long time and he's been very successful," Blue Jays manager John Gibbons said. "He shuts down good-hitting teams, he's a great competitor."
Todd Redmond worked the eighth and Rob Rasmussen finished.
Red Sox right-hander Rubby De La Rosa allowed seven runs, six earned, in a season-low four-plus innings, raising his ERA from 2.64 to 3.54.
"He had a hard time neutralizing their left-handed hitters," Farrell said. "Francisco had big day."
De La Rosa (3-3), who lost for the first time since June 11 at Baltimore, walked two and struck out one. He's 0-3 with a 6.04 ERA in four road starts, but 3-0 with a 1.38 ERA in four starts at Fenway Park.
"I try to have everything the same," De La Rosa said of the disparity. "It doesn't make sense for me."
Francisco tripled and scored in the second, hit a two-run homer in the third and added a two-run single in the fifth as the Blue Jays won for the fifth time in six games.
Blue Jays outfielder Melky Cabrera went 3 for 4 with a walk and two RBIs. Cabrera scored a run and doubled three times.
After getting the day off Wednesday, Red Sox rookie Brock Holt returned to the lineup at second base. Holt has started at every position this season except pitcher, catcher and designated hitter. Dustin Pedroia, who is stuck in a 2-for-24 slump, got the day off.
Cabrera opened the scoring on a bases-loaded passed ball in the first. Toronto made it 3-0 in the second when Francisco tripled off the glove of Jackie Bradley Jr. and scored on Ryan Goins' double, with Goins coming home on Cabrera's first double.
Francisco made it 5-0 with his two-out homer in the third, then added a bases-loaded single off Burke Badenhop in the sixth.
Toronto loaded the bases with one out in the seventh, but Badenhop got Dan Johnson to ground into a double play.
Cabrera made it 8-0 when he doubled home Jose Reyes against Edward Mujica in the eighth.