Lester (17-8) held Seattle to just three hits over eight innings and the Red Sox beat the Mariners 5-1 on Monday night.
He has won four straight decisions and six of his past seven starts. He gave up three singles, two to Chone Figgins, walked three and struck 12. It's the seventh time this season he has struck out 10 or more.
Lester moved over the 200-strikeout plateau for the second straight season. He is the fifth pitcher in Red Sox history to have back-to-back 200-strikeout seasons, joining Roger Clemens, Pedro Martinez, Cy Young and Smokey Joe Wood.
"It's nice. It's something to look back on when I'm done playing," Lester said. "Right now it doesn't really make or break my season. We're trying to make the playoffs. That's where we evaluate our season, whether we're in the postseason or not."
It appears the Red Sox might strike out in the postseason. They are seven games behind the New York Yankees in the wild-card chase with 18 games remaining. But the Sox have six more games to play against the Yankees.
Lester now is tied for second in the American League in wins. He is third in strikeouts (208), eighth in ERA (3.17) and tied for third in opponents batting average (.220).
"He's got a great cutter and two-seamer, too," Tuiasosopo said of Lester. "You can't try to hit the cutter cause he'll throw the two-seamer away. He's tough. There's a reason why he is one of the best."
In his last start July 24 at Safeco Field, Lester retired the first 17 batters but the Mariners rallied for a 5-1 victory. Lester struck out a career-high 13.
That's 25 strikeouts in his past two starts at Safeco. Over his past four starts, he has had four straight double-digit strikeout games, the longest streak for any pitcher this season.
"Nothing's changed, just getting more swings and misses, executing pitches," Lester said. "I'm throwing the same pitches I've been throwing all year. It's a matter of locating them down in the zone. I've been able to do that.
"There are situations where you try to strike guys out but for the most part I throw pitches and hopefully get them out early in the count. If not, you go from there. I don't consider myself that [strikeout pitcher]."
Red Sox manager Terry Francona said maturity has made Lester a better pitcher.
"His maturation and the development of his curve, change and cutter and adding velocity. That's a pretty good mix," Francona said. "He can attack both sides of the plate. He changes speeds. He can attack both lefties and righties. When he's throwing the ball like he wants to, he has a lot of ways to get hitters out."
The Red Sox took a 3-0 lead in the second, hitting three doubles. Adrian Beltre singled to open the inning. Jed Lowrie doubled, sending Beltre to third. He came home on Josh Reddick's groundout. Daniel Nava and Lars Anderson followed with consecutive RBI doubles.
"You get a couple runs on board and you can kind of sit back a little bit, minimize the damage," Lester said. "It makes things easier, takes the pressure off."
"It was once again a matter of leaving pitches up," Fister said. "I made some pitches but when it came down to making a pitch, left it up."
The Mariners scored their run in the seventh. Franklin Gutierrez drew a one-out walk. Lopez singled to left, pushing Gutierrez around to third. He scored on Kotchman's infield groundout.
Boston bullpen coach Gary Tuck took over the pitching coach role. Regular pitching coach John Farrell missed game because of a kidney stone attack.
Ichiro Suzuki went 0-for-4, ending his 13-game hitting streak.
The Red Sox have added LH Rich Hill to their roster. Hill, a five-year veteran whose best year was 2007 when he was 11-8 with the Cubs, signed as a free agent on June 30. He had been released from the Cardinals organization. "Maybe it's a nice chance to learn more about him," Francona said. ... J.D. Drew missed the game with a slight sprained ankle. He turned his ankle rounding first base Sunday. ... Mariners closer David Aardsma is one save short of getting 30 for the second straight season. He had none before last year. "He's taken to that job. He understands it," manager Daren Brown said. "It takes a special type person to come in at the end of the ballgame. Things don't bother him and he's able to get the job done."