Hits with runners in scoring position are becoming routine for Boston's new slugger.
Cespedes had four hits, including the game-winning single that capped a three-run 10th inning, and the Red Sox rallied to beat the Toronto Blue Jays 9-8 on Friday night.
"He's proven to us time and time again in RBI situations, he's got a knack for it," Boston manager John Farrell said. "He's aggressive, he's strong and he's got all-field coverage."
Since coming over from Oakland at the July 31 trade deadline in a deal for lefty ace Jon Lester, Cespedes has 26 RBIs in 32 games and a .421 batting average with runners in scoring position. With the bases loaded, he's 6 for 9 with 12 RBIs for the Red Sox.
"Kind of like (David) Ortiz," Boston shortstop Xander Bogaerts said. "I don't know if they share tips with each other, but when he sees guys on base he just drives them in."
Toronto, which lost outfielder Melky Cabrera to a season-ending pinkie injury, took an 8-6 lead in the top of the 10th. The first run scored on Dioner Navarro's infield single that followed a single by Edwin Encarnacion and a double by John Mayberry Jr.
Danny Valencia then hit a deep fly to right fielder Allen Craig, who caught what he thought was the third out. By the time he realized it wasn't, Mayberry was on his way to scoring all the way from second on Valencia's unusual sacrifice fly.
"You score those two runs in the top of the 10th there, so you're feeling really good and then bam, bam, bam, bam," Toronto manager John Gibbons said. "Nine times out of 10 we win that game."
Will Middlebrooks singled in Betts, and Boston tied it on Dustin Pedroia's sacrifice fly. Ortiz hit a soft grounder to second baseman Steve Tolleson, but his toss to second hit Middlebrooks for an error that left the bases loaded.
Cespedes then connected and Weeks, who ran for Vazquez, scored easily.
"I felt great," Janssen said. "I truly believed I was going to get out of it."
Tommy Layne (2-1) got the win.
"If you look at the last three innings, it was a wild stretch of the game," Farrell said. "More importantly is how we continued to respond."
Boston's first three-run comeback tied it 6-all in the eighth after Jose Bautista and Encarnacion each reached the 30-homer mark with a two-run shot. Bautista's made it 4-3 in the sixth, and Encarnacion's gave Toronto a 6-3 lead in the eighth.
Blue Jays: Cabrera will undergo season-ending surgery next week for a broken right pinkie. He left in the sixth inning for X-rays. He appeared to injure his finger in the third when he dove back into first base while being picked off. "I wanted to finish strong and help the team get to the playoffs," he said.
Red Sox: Pedroia returned to his usual No. 2 spot in the lineup after missing five games with a concussion. ... 3B Brock Holt was replaced in the top of the 10th by Middlebrooks after feeling dizzy.
J.A. Happ (9-8) pitches for Toronto against Boston RHP Clay Buchholz (6-8) in the second game of the three-game series Saturday night. They faced each other in Toronto on Aug. 25, when Buchholz went 8 1/3 innings and Boston won 4-3 in 10 after allowing the Blue Jays to tie with three runs in the ninth. Buchholz's 10 career wins against Toronto are his most against any opponent.
Red Sox rookies Betts, Bogaerts and Vazquez were 7 for 13 with four RBIs from the last three spots in the order. "We got three young guys to start something going and I'm glad all of us got something done so the other guys could drive us in," Bogaerts said.
Toronto led 2-0 on Adam Lind's two-run single in the first and then fell behind 3-2 as Boston scored a run in each of the first three innings. Then came Boston's two three-run rallies late in the game. "We didn't give up," Bogaerts said.