In one of his best outings of the season, the left-hander, who won at least 15 games in each of the last four seasons, allowed three runs and seven hits on Thursday night. And he lasted eight innings for just the third time in 22 starts.
But the Boston Red Sox managed only two hits against Samuel Deduno and two relievers and lost 5-0 to the Minnesota Twins.
"I don't feel like I have thrown the ball that well all year," Lester said. "I need to keep sticking with the process. Obviously, the results aren't there and a loss is a loss."
Lester (5-9) is 0-4 in his last six starts in a season that hit bottom when he gave up 11 earned runs in four innings on July 22 in a 15-7 loss to Toronto.
He had allowed 25 runs in his four starts before Thursday but improved in his last one, giving up four runs in six innings. And he was much better on Thursday despite dropping to 0-4 in his last six starts and 2-7 at Fenway Park this season.
"It's just another one of those hard luck outings," Boston manager Bobby Valentine said. "He pitched awfully well. 2-0 doesn't seem insurmountable but it was tonight."
The Twins took a 2-0 lead in the third, but Lester allowed only four hits in his remaining five innings and retired his last seven batters.
"He can get on a roll as well as anyone in this league," Valentine said.
All of Minnesota's runs came with two outs, a problem that has plagued Lester this year.
"If I had the answer it wouldn't happen," he said.
Deduno (3-0) has allowed just two hits in his last two starts but struggled with his control.
He walked four and struck out one in six innings before two relievers combined for three perfect innings. In his previous start, he allowed one run, two hits and five walks in seven innings in a 12-5 win over Cleveland.
"I know his ball-strike ratio wasn't the greatest, but sometimes that works," Twins manager Ron Gardenhire said. "He was able to make pitches when he had to and that's all you really care about."
Deduno had an outstanding curveball and slider. He also has a fastball that moves so much that his catchers sometimes wonder where it will end up. And it led to him throwing only 50 of his 101 pitches for strikes.
Deduno, making his sixth major league start, has given up just two earned runs and 10 hits in 19 1-3 innings in his last three outings.
"My curveball and my slider are pretty good, but my fastball is still moving like crazy," said Deduno, who reached the majors in 2010 and pitched six games in relief for Colorado and San Diego. "This is the most fun. This is the dream to play in the big leagues and to stay not just for one month or two months."
Adrian Gonzalez got both Boston hits, a single and double. Casey Fien retired the side in order in the seventh and Glen Perkins pitched two perfect innings for his sixth save in nine opportunities.
The Twins took a 2-0 lead in the third inning on a single by Brian Dozier, an RBI double by Denard Span and a run-scoring single by Ben Revere that extended his career-best hitting streak to 16 games. They made it 3-0 in the sixth on consecutive doubles by Justin Morneau and Ryan Doumit. Dozier added his third hit of the game and fifth homer of the season, a two-run shot in the ninth off Alfredo Aceves.
"That was pretty cool, man. It was one of the best feelings so far since I've been up here," said Dozier, who was called up from Rochester on May 7.
The Twins won for the fifth time in seven games, while the Red Sox dropped their second straight after winning four in a row.
Deduno allowed just three runners to reach second base.
With two outs in the first, he walked Dustin Pedroia and Gonzalez then retired Cody Ross on a popup. In the third, Gonzalez doubled with one out, Ryan Lavarnway walked with two outs but Will Middlebrooks flied out to center. And with two outs in the sixth, Boston threatened with consecutive singles by Gonzalez and Ross before Lavarnway lined out to left.
Notes: Span stretched his hitting streak to 11 games. ... Gonzalez went 2-for-3 with a walk, his 18th muiltihit game in his last 34. ... Minnesota C Joe Mauer was given the night off to rest. He is hitting .352 in his last 57 games. ... The Red Sox stranded runners in scoring position in three of the first six innings. ... Minnesota's Brian Duensing (2-6) is scheduled to pitch Friday night's second game of the four-game series against Felix Doubront (10-5). ... Boston is 10-10 since the All-Star break. And 289-291 all-time against Minnesota.
This program aired on August 3, 2012. The audio for this program is not available.