It wasn't enough for him to become the majors' first 10-game winner.
He allowed another solo shot to former teammate George Kottaras, giving up four runs in the first three innings, but settled down and pitched through eight.
"We lost," said Lester (9-3) when asked if he was pleased with how he rebounded. "You can sit back and say there were some positives. With the way it started, it could have been a lot worse. I just tried to minimize the damage and keep the guys in the game.
The Red Sox had averaged 7.7 runs per game in winning 12 of their previous 13 games. But Randy Wolf (5-4), a lefty who changes speeds, gave up two runs that tied the game in the second and then lasted through seven, scattering nine hits. Relievers Kameron Loe and John Axford pitched an inning apiece, with Axford earning his 19th save.
"Obviously, with the way we've been swinging the bats lately, I thought for sure if I just kept them where they were at we'd have a chance," Lester said. "But you've got to tip your hat to Randy Wolf tonight. He threw the ball better than I did. That's the main thing: You've got to outpitch the other guy. He did that tonight."
Weeks became a statistical oddity in the first inning when Red Sox first baseman Adrian Gonzalez dropped his foul pop and then Weeks hit the next pitch for a home run, becoming an unearned run as the leadoff hitter of a game. He became the first player to lead off a game by having his foul pop dropped before hitting a home run since Warren Cromartie of the Montreal Expos homered off Bill Caudill of the Chicago Cubs — after third baseman Steve Ontiveros dropped Cromartie's foul fly, July 4, 1979, according to information provided to the teams by the Elias Sports Bureau.
Hart then homered on the next pitch and Kottaras, who played for the Red Sox in both 2008 and '09, homered to lead off the third.
Following two outs, Lester lost the strike zone and walked Ryan Braun and Price Fielder before Casey McGehee singled home the fourth run.
The three homers matched a career high for Lester, who also yielded three opening day. He has allowed 14 homers this season, matching his total for last year.
"I haven't given it enough thought. I probably should," Red Sox manager Terry Francona said of Lester's home run total.
As far as his lefty's outing, the manager said: "After (the third), he put up five zeros. We just couldn't get anything going."
Wolf got out of trouble after the Red Sox tied it. He left runners on first and second in the third and allowed a leadoff double to Marco Scutaro before retiring the next three batters in the fourth.
Boston had won its last 11 when facing a left-handed starter, its longest stretch since 13 in a row in 2008.
Notes: It was Weeks' fourth leadoff homer this season. ... The Red Sox placed LF Carl Crawford on the 15-day DL before the game with a strained left hamstring. He suffered the injury beating out an infield hit in Friday's 10-4 win. ... Brewers manager Ron Roenicke said RHP Shaun Marcum, who left Friday's game with a left hip flexor, was expected to be checked out by a doctor at Fenway Park on Saturday night and again by the Brewers medical staff on Monday. "He was scheduled to throw a side on Monday, but he may have to skip a start," Roenicke said. ... The game was moved from a scheduled 1:10 start to 7:10 to help reduce congestion around the city as many fans were attending a "Rolling Rally" in the afternoon to celebrate the Boston Bruins winning the Stanley Cup. ... Boston closer Jonathan Papelbon served the second of his three-game suspension handed down for bumping plate umpire Tony Randazzo on June 4.