With several scouts and Red Sox assistant general manager Jed Hoyer watching from behind home plate, Lester needed just eight pitches to retire Alexi Casilla, Glenn Williams and Mike Redmond. Lester threw eight pitches, six for strikes, to catcher George Kottaras.
"I tried to treat it as much as a normal game as I could," Lester said. "I tried not to get too amped up and tried not to worry about it and just get a good night's sleep and come in here and get my work done and go on and build from here."
Six of the pitches were fastballs. There were no fewer than three radar guns on his pitches, with three fastballs clocked at 88 mph, two at 89 mph and one at 90 mph.
"I was trying to throw as hard as I could," he said. "I was trying to make it as game-like as possible and get that adrenaline going again."
His two other pitches were curveballs to Williams after he got ahead of the third baseman at 0-2. He bounced both for balls before retiring him on the grounder to third.
"Command was great," Lester said. "I went away when I wanted to go away and went in when I wanted to go in. I was in the general vicinity [with] all my pitches. I don't know what the velocity was. It felt good. We'll just build from here and hopefully get stronger as camp goes on, and if the velocity isn't there, hopefully it will build back up to normal."
It was Lester's first game action since Aug. 23, when he allowed six hits and three run and earned a win against the Angels in Anaheim. Nine days later, the club and Lester announced he had a rare non-Hodgkin's form of lymphoma.
After his work on Monday, Lester, who finished last season 7-2 with a 4.76 ERA, felt confident enough to declare that his offseason cancer treatments are not impacting how he prepares this spring.
"I don't think the treatments are a factor right now," he said. "I'm still building it back up from the offseason, but I think I'm right about at 85 or 90 percent, getting close and starting to feel a little more comfortable with my body and how things are flowing."
Another lefty, Kason Gabbard, replaced Lester on the mound to start the second inning. The Twins started right-hander Sidney Ponson, who threw two scoreless innings.