Over four-plus innings, he gave up nine hits and eight runs, walking five and striking out five.
"Coming out of the bullpen, I felt OK," said Lester. "It was just one of those days. It was a bad day to have one of them. Obviously, [I] would have liked to end on a little better note, but that's the way it is."
However, one subpar start could not diminish a stellar season for the 26-year-old Lester, who finished 19-9 with a 3.25 ERA and notched 225 strikeouts over 208 innings.
"Like I've said all along, it's more disappointing not making the playoffs than it is [not winning 20]," said Lester. "Would it have been nice? Yeah. I'm not going to lie to you. Regardless of all that, we didn't make the playoffs. We didn't meet our goal this year. And that's more disappointing than the win/loss record or whatever else you want to put on it."
Sure, Lester knew he was one away from 20. But he doesn't feel it had any impact on the way he pitched.
"I did think about it," Lester said. "You know, it's something that is obviously there and you can't hide from it. I don't think it had any bearing on the outcome of tonight's game. I just didn't go out and execute pitches. Regardless of it's the 20th or the first win of the year, that's the main thing it comes down to. [I] didn't execute pitches and got myself into a lot of jams that I couldn't get out of."
Juan Pierre led off Chicago's first with a single to left. He stole second and third before scoring on an RBI single to left by Andruw Jones.
In the third, the Red Sox stole the momentum back as Victor Martinez belted a two-run homer to left, No. 20 on the season. For the switch-hitter, it was Martinez's 12th long ball from the right side.
But it turned into a very minor nuisance for the White Sox, who came right back to tie it in the bottom of the third on an RBI single to right by Jones.
"I thought we made him work," said White Sox manager Ozzie Guillen. "We had a lot of pitches early. Four innings, he has more than 80 pitches. Our offense did a tremendous job and made him throw pitches. I think the key in every game is throw strikes. And he wasn't throwing strikes the way he always does, and that's why he got in trouble."
Everything fell apart for Lester and the Red Sox in the bottom of the fourth. After a one-out double by Alejandro De Aza, Lester issued two-out walks to Pierre and Alexei Ramirez. That was extremely costly, as Konerko walloped that grand slam -- the first allowed by Lester in his career. It gave the White Sox a 6-2 lead.
"I threw a fastball up and he hit it out," said Lester. "He's obviously having a great year. Any time you throw a fastball up to those guys that can do what he can, it's not good. If I locate it, does he hit a ground ball? Maybe. Does he still hit it out? Maybe. I don't know. I threw it up in the zone and kind of provided a little bit of the power for him. He put a good swing on it. You've got to tip your hat."
And yes, Lester knew he had never given up a grand slam in the Majors.
"It's one of those things, it's kind of hard not to realize," Lester said. "You know, hopefully I give up a couple of more. It means I'm pitching a long time. I'll move on."
Things continued to sour in the fifth, when Dayan Viciedo ripped a two-run homer. After a four-pitch walk to Brent Morel, Lester was removed from the game, officially ending his quest for a 20-win season. The last Boston pitcher to win 20 games was Josh Beckett in 2007.
"Konerko saw a lot of pitches and it changes the whole complexion of the game," said Red Sox manager Terry Francona. "Instead of being 2-2, now it's 6-2. Then he goes back out and gives up the home run. That was enough."
The game was delayed for 21 minutes in the bottom of the sixth inning by a power outage that impacted the neighborhood surrounding U.S. Cellular Field.