David Ortiz jump-started Boston's sluggish offense with a three-run homer, Adam LaRoche added a two-run shot in his Red Sox debut and Lester worked into the eighth inning in a 7-2 win over the struggling Orioles on Saturday night.
Lester (9-7) improved to 9-0 in 11 career starts against Baltimore, and the Red Sox beat the Orioles for the 11th straight time at home.
"I don't think we were pressing tonight," Boston manager Terry Francona said. "Last week, we were saying guys were trying to swing for a three-run homer. Every team goes through periods where things aren't going very well and you try too hard."
Baltimore, which lost for the 14th time in 18 games, fell to 1-16 in road games within the division.
How the Orioles play the rest of their games against the Yankees, Red Sox and Tampa Bay Rays may be the difference in the AL East. Baltimore is 0-6 in both Fenway and Yankee Stadium this season, and 1-1 against the Rays in Tropicana Field.
"It's not from a lack of effort, that's for sure. We've played a lot of close games," Baltimore's Brian Roberts said of his team's lack of success in Fenway.
Lester was mostly in control, giving up two runs and eight hits in 7 1/3 innings. He struck out nine and walked two. He allowed both of the runs in the fourth on RBI singles by Matt Wieters and Cesar Izturis.
"The way he's throwing, I'd hate to say it doesn't matter [who he's facing], but if he pitches like that he's going to be OK," Francona said.
Unlike the previous six games when the Red Sox struggled to score, they jumped on Jeremy Guthrie (7-9) for three runs in the first on Ortiz's 13th homer. Dustin Pedroia walked and Jason Bay had a two-out single before Ortiz's high drive carried into the center-field seats.
"It definitely eases a pitcher's mind when we go out and get some runs early," Lester said. "You still have to have the mental edge, but you do have a little room to work with."
LaRoche, acquired from Pittsburgh on Wednesday for two minor leaguers, went 1 for 4. His opposite-field homer went into the first row of Green Monster seats off Mark Hendrickson in the eighth.
"It definitely feels good. I had gotten away from that a little bit," LaRoche said of trying to hit the other way.
The Red Sox were held to four or fewer runs in all of their previous seven games since the All-Star break.
Guthrie, coming off one his best starts of the season when he held the Chicago White Sox to three hits and two runs in a 10-2 win last Saturday, gave up his AL-leading 23rd homer.
"Some players maybe," Guthrie said when asked if they may be thinking about the losing streak in Boston. "I can't speak for everybody. I know that personally for me, ever since the first game I've thrown here, it's been one thing after another that leads to crazy things."
The three-run first was Boston's most in an inning since the last game before the break. ... Red Sox 1B/3B Kevin Youkilis was rested so 1B LaRoche could start. "[Youkilis] is a little beat up. I just thought it was a good night to go ahead and do it," Francona said before the game. "This isn't going to be like a rotation." Youkilis may have been a bit surprised by the time off after the team had an off-day Thursday. "We haven't discussed it much. They told me today's my off day," he said. ... Baltimore's sidelined right-handed pitchers Dennis Sarfate (circulatory condition) and Chris Ray (biceps tendinitis) each threw a scoreless inning in a rehab appearance with Triple-A Norfolk Friday. ... Plate umpire Paul Neuert had his mask knocked off by a ninth-inning foul tip.