The defending World Series champions have dropped seven in a row after Thursday's 7-2 loss to the Blue Jays capped an 0-6 homestand.
The last time Boston had a winless homestand of six games or more was from June 10-15, 1994, against the Orioles and Twins.
"It starts with the guys that begin the game on the mound," said manager John Farrell. "We've got to set the tone with our rotation. We've got to keep an opposing offense in check to give us some opportunities to capitalize on. That's not happening through these last seven games, obviously."
Not even Jon Lester could help the Red Sox avoid their worst homestand in 20 years.
In fact, the lefty gave up seven runs over the first two innings against the Blue Jays.
"It's crazy," said Red Sox slugger David Ortiz. "We were just talking about it in the shower, a couple of the guys. It's crazy seeing things going down like that. We've just got to come back out and start playing better, man."
The quest to start playing better will start on Friday night when the Sox open a three-game set against the Rays at Tropicana Field.
Clearly, Lester had hoped to give his team a better sendoff.
"It's not fun going out there and giving up a bunch of hits," Lester said. "I'm trying to stop a losing streak, trying to win, trying to keep guys in the ballgame. The list goes on and on of things I flat-out didn't do today."
While pitching always sets the tone, the Red Sox know they also aren't hitting well enough to win.
"It's like a disease going around," Ortiz said. "Nobody's really doing much. We're going to need to go back in and try to do something -- something different."
Though Lester settled down nicely, keeping the Jays off the board for the rest of his outing, he dug too big a hole against Mark Buehrle.
Toronto's lefty ran his record to 8-1 by scattering seven hits and two runs over seven innings, walking none and striking out five.
"He just works fast and throws it over the plate," Red Sox catcher A.J. Pierzysnki said of his former teammate. "He knows he has room to work, and that's what he did. We hit a lot of balls hard and they made a lot of nice plays. Any time you give a guy that's going to throw it over the plate and work fast, and throw strikes and not give you extra baserunners, it's tough."
Lester (4-6, 3.36 ERA) gave up 10 hits and seven runs over 6 1/3 innings, walking two and striking out three.
"We're in a stretch of games here where we're giving up too many runs early and we're scuffling to score runs," Farrell said. "That's a dangerous combination right now."
For Lester, the day started exactly the way he didn't want it to. Melky Cabrera and Jose Bautista belted back-to-back solo shots over the Monster to put the Red Sox in a 2-0 hole before they even took a swing.
Dustin Pedroia gave the Red Sox some hope in the bottom of the first with a double to left. Jonny Gomes lined an RBI single to make it 2-1.
But Lester got into big trouble in the second. After giving up back-to-back singles and a sacrifice bunt, Jose Reyes ripped a two-run single. Lester walked Cabrera. Bautista and Edwin Encarnacion followed with RBI singles.
Brett Lawrie capped the damage in the five-run frame with a fielder's choice grounder, and the Red Sox were pinned in a 7-1 hole.
"I've got to do a better job in the second inning minimizing damage," Lester said. "A ball that gets chopped off the plate, if it's hit a little harder, we get an out, maybe two, but that's neither here nor there. I've got to flat do a better job in that second inning of minimizing damage and do a better job of getting these guys back in the dugout, especially after that first inning when we put up one and we're trying to keep a little bit of momentum on our side, and I flat-out didn't do it."
Xander Bogaerts got one of the runs back with a towering homer to left in the third.
Bogaerts has been on a tear of late, with nine hits in his last 18 at-bats.
"I'm just seeing the ball good," Bogaerts said. "I made some adjustments. I'm hitting the ball good right now, but we're not winning so it's frustrating."
Frustration is a buzzword in Boston's clubhouse right now.
"You can't start winning games thinking we're going to win 10 in a row," Pedroia said. "No, we're going to win the next pitch. That's how we have to start thinking."