TORONTO -- The Red Sox clawed and battled all game after playing the majority of Tuesday night's contest from behind.
And once Boston finally gained its first lead of the game and silenced a crowd of 22,195 in the seventh, it was quickly relinquished in the bottom half of the frame and the team never recovered.
Junichi Tazawa surrendered a two-run homer to Edwin Encarnacion in the seventh inning, resulting in the pivotal blow in the Red Sox's 9-7 loss to the Blue Jays in the first of a three-game set at Rogers Centre.
"One mislocated pitch," manager John Farrell said about Tazawa's location. "It just didn't stay to the spot down and away, and Edwin put a good swing on it.
"Edwin's a very good hitter. Obviously he has been very productive here the last couple years."
With two outs and none on, Tazawa walked Jose Bautista before Encarnacion blasted the two-run shot to center field for his second homer of the game, putting Toronto ahead, 8-7. Encarnacion also hit a two-run shot into the 500 level in left field in the fifth inning off starter Jon Lester.
It wasn't Lester's strongest performance, and he said he felt bad that Tazawa was credited with the loss when it was the lefty who put the Red Sox in a hole. The two earned runs Tazawa surrendered on the Encarnacion homer marked the first time he has allowed more than one earned run in a game since Sept. 4, 2009, a span of 53 games.
"That's a tough spot and I'll take Tazawa 10 out of 10 times in that matchup," said Lester, whose six runs allowed (five earned) were his most since surrendering 11 to the Blue Jays last July. "That's a tough one for Taz. Those are the ones you wish you could flip flop with him, but next time he'll pick me up. I'm not worried about it."
Tazawa entered the seventh with a 7-6 lead thanks in large part to David Ortiz, who has been on an absolute tear to start his season.
After the Blue Jays botched a double-play ball that would have potentially ended the frame, Dustin Pedroia walked to load the bases for Ortiz, who cleared them with a three-run double to right. Ortiz drilled a 3-1 fastball off reliever Steve Delabar to put Boston in front, 7-6.
Ortiz also hit a solo homer, his third of the year, in the fourth inning to put the Red Sox on the board. Ortiz is batting .500 with a whopping .917 slugging percentage and 15 RBIs over just nine games this season.
"He continues to, not only just step into our offense, but come up big in many situations," Farrell said. "He has just done an outstanding job for us."
The designated hitter was one of three Red Sox to go deep in the contest.
Mike Carp hit his first home run two batters after Ortiz went deep in the fourth off Blue Jays starter Brandon Morrow, and Jonny Gomes hit a pinch-hit homer, also his first with Boston, in the sixth inning.
Boston's offense bailed out Lester, who struggled for the second consecutive start, from taking the loss.
Lester surrendered a run in the first and three more in the third after a bizarre play led to a pair of Toronto runs.
The left-hander allowed the first three runners of the inning to reach base by giving up a leadoff single, hitting Rajai Davis with a pitch and then walking Bautista on four straight pitches. Things really unraveled after that.
With Encarnacion at the plate, catcher Jarrod Saltalamacchia attempted to pick off Bautista at first base, but he threw the ball wide of the bag and into right field, which allowed two runs to score and put the Blue Jays in front, 3-0.
It was revealed postgame that Saltalamacchia hit home-plate umpire Clint Fagan on the throw, which is the reason the ball sailed into the outfield.
"I went to go throw it and my elbow hit the umpire's mask," Saltalamacchia said.
Since Saltalamacchia made contact with the umpire, it should have been a dead ball. However, he didn't know the ruling on the play and it's something he has done before.
Saltalamacchia talked with Fagan after the frame, but Fagan said that he hit him on the follow through, not when he cocked back to throw, which the backstop disputes.
"It's kind of impossible," Saltalamacchia said.
Even with the bases loaded and Saltalamacchia throwing behind the runners, Farrell said it was absolutely the right play based on the catcher's usual accuracy and how much Bautista was off the bag. The throw was supposed to be to the inside part of the base.
Lester had to battle all game and used 100 pitches to get through his six innings of work. He allowed six hits while walking two and striking out five. This came after issuing a season-high six walks in his last start against Oakland. The southpaw said he didn't feel right from the beginning of the game and wasn't throwing any pitches with the polish that he should have been.
Farrell thought Lester had trouble finishing his cutter, which left the pitch a little flat in the zone. The mammoth homer Encarnacion hit out was off a cutter.
"It felt very good, but I never thought it was going to go that far, but I hit the ball good," Encarnacion said.
Morrow wasn't sharp either, lasting just five innings while allowing three runs on six hits. He came out gunning, punching out five consecutive at one point, before the Red Sox got to him in the fourth.
Despite the loss, which snapped Boston's five-game winning streak and prevented the team from setting a club record for wins in April, the Red Sox ended the month with the best record in baseball for the 11th time in franchise history.
Chris Toman is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.