Of Boston's 11 wins during that magical run to the World Series championship, Lester had four. And the one game he lost was 1-0.
That October for the ages was Lester's true coming of age, and it makes him even more confident as he helps the Red Sox open their title defense.
"You're playing on the biggest stage at the biggest time of the year," said Lester. "To go out there and perform and be successful, that can boost you. Especially those days you're not feeling so good, especially that time of year, you learned, 'Hey, I don't need to be blowing 96 [mph] in order to get guys out.' You can pitch and maneuver through lineups, and when you do it on that stage, absolutely it boosts your confidence going into the next year."
So here Lester is at 30, not only smack in the middle of his prime but now with the wealth of his experiences over the years.
As a rookie, Lester was forced to battle cancer, and he overcame that. In his second year, he won the World Series clincher in Colorado after spending most of that season regaining his strength.
From 2008 to 2011, Lester was a rock of consistency, his fastball and cutter leading to four straight seasons of 15 wins or more.
Then came 2012, when he struggled mightily as a pitcher for the first time in his life. Instead of letting that bring him down, he bounced back with a solid regular season in 2013 and that dominant postseason, in which his ERA was 1.56.
"We all as kids want to be that guy -- the guy who goes into the playoffs and puts up good starts and good numbers and all that. That's probably the most satisfying thing -- I was able to do that for my teammates," Lester said. "When we needed to get off on the right foot and set the tone, I was able to do that."
There aren't all that many pitchers in history who have been quite as locked in as Lester was during Boston's finishing run in 2013. Perhaps only those who have experienced it know exactly what it is like, and how empowering it can be.
"You know, for me, after the '95 postseason, that was kind of the one that I put in the archive, so whenever I was struggling, that was the tape I went back and watched to see if I could find something wrong or get to the point where you feel good about yourself again," said lefty Tom Glavine, who was recently elected to the Hall of Fame.
"It's a lot of fun, and you don't want it to end. You do, obviously, from the standpoint of you want to win the World Series and you know that's the ultimate conclusion to it. But when you're on a roll like that and pitching that way under those circumstances, it's a lot of fun. That's where you want to be."
Lester is one of the lefties Glavine enjoys watching most.
"Being a Red Sox fan still, I love watching him pitch. I loved watching him in the postseason last year. That's the style of pitching that I like," Glavine said. "He obviously throws hard, but it's not all about throwing the ball by people. He's thinking about what he's doing, he's mixing his pitches up well, and I love his competitiveness. He takes the ball and looks like he just has the attitude when he goes out there that 'I'm going to beat you.' I like seeing that kind of attitude."
If a Hall of Famer talks about Lester with that type of reverential tone, perhaps Lester will one day find himself headed for Cooperstown.
For now he will just focus on each season as it comes, and he can't wait for this one.
Though it's hard to imagine Lester can produce a better October than the one he just did, it's possible that his best regular-season stat line is still in him.
"Obviously, each year you look to improve and get better. Obviously, with last year I had some ups and downs," said Lester. "I came out like gangbusters, but I think I peaked a little too early. The biggest thing for me is how I finished. Hopefully, I can take that same point and carry it over to this year."