TORONTO – Another day, another game of missed opportunities for the struggling Red Sox.

Pinch-hitter Mark DeRosa hit a tiebreaking sacrifice fly in the seventh inning, Mark Buehrle pitched seven innings to win his fourth straight decision and the Toronto Blue Jays beat Boston 2-1 on Thursday night.

“Tonight the story is (runners) left on base,” Red Sox Manager John Farrell said. “This is a frustrating one.”

The Red Sox went 2 for 12 with runners in scoring position and left 12 on. That dropped them to 6 for 34 with runners in scoring position in the three-game series and boosted their total of stranded runners to 33.

“We had a ton of opportunities to score and just couldn’t get that one big hit,” said Dustin Pedroia. “We’ve got to swing the bats better with guys on.”

The Blue Jays took 2 of 3 from the AL East-leading Red Sox, who went 4-6 on a three-city trip that also included stops in Houston and Kansas City. Boston has lost 5 of 7 overall, dropping consecutive series for the first time since losing three straight against Texas, Minnesota and Toronto from May 3-12.

“Anytime you go through a 4-6 road trip it’s disappointing,” said Farrell. “We’ve got to go home and regroup.”

The Red Sox won’t get much time to enjoy being home. After a three-game series with the Yankees that begins Friday, they hit the road again for three at San Francisco and three against the NL West-leading Los Angeles Dodgers.

Buehrle (9-7) came in 0-4 with a 4.97 ERA in his previous eight starts against the Red Sox, a team he hadn’t beaten since Sept. 7, 2009, with the White Sox.

“I know I’ve struggled against them,” Buehrle said. “You have to have everything going your way. You have to have runs scored for you, you have to have defense behind you and you have to have the bullpen save the lead.”

Buehrle allowed one run and 10 hits, walked two and struck out four before Darren Oliver worked the eighth and Casey Janssen finished for his 22nd save in 24 chances.

Pedroia hit a two-out single in the first and went to second when David Ortiz walked, but was thrown out at the plate by left fielder Kevin Pillar while trying to score on a Jonny Gomes single. It was the first assist of Pillar’s career.

Pedroia said he didn’t slide because he was hoping to let the ball hit him. Instead he ran beyond the plate and tried to come back, only to be tagged out by catcher J.P. Arencibia, who was waiting with the ball.

“It was kind of an awkward deal,” Pedroia said. “I should have tried to slide or go through him or something.”

With the Blue Jays using a defensive shift, Pedroia was able to go from first to third when Ortiz grounded out in the third. Toronto escaped when Gomes fouled out and Stephen Drew struck out.

After stranding six runners through the first three innings, Boston broke through with a run off Buehrle in the fourth. Daniel Nava hit a one-out double, went to third on a check-swing single by Will Middlebrooks and scored on Jacoby Ellsbury’s RBI grounder. The Blue Jays might have been able to turn a double play but second baseman Munenori Kawasaki threw high to shortstop Jose Reyes covering second, preventing a throw to first.

Drew and Ryan Lavarnway singled to begin the sixth, but Buehrle struck out Nava and Middlebrooks before getting Ellsbury to ground out.

Red Sox starter Jake Peavy (9-5) came in 2-0 with a 2.15 ERA in his past four starts against Toronto and was untroubled through six innings, allowing just a pair of two-out hits.

That changed in the seventh, when Jose Bautista singled off the glove of third baseman Middlebrooks, took second on Edwin Encarnacion’s single and scored on a base hit by Lawrie.