"He pitched really well," Red Sox manager Terry Francona said. "I think he ought to feel good about himself. He looks great."
It was the second good start in a row for Lester, who threw 119 pitches with 75 strikes. He allowed two walks, both to Mike McCoy, but the only hit was a leadoff double by Vernon Wells in the second.
"Jon keeps taking steps," catcher Jason Varitek said. "I think he took himself to another step today."
"He did a great job behind home plate mixing all the pitches in," Lester said.
Lester's ERA dropped from 6.23 to 4.71 after the outing as he bettered another left-hander, Brett Cecil, who gave up five hits and one run in six innings.
McDonald led off the sixth with a double to left-center field, and Marco Scutaro's single sent him to third. Dustin Pedroia's sacrifice fly scored McDonald to put Boston ahead, 1-0.
McDonald drove in a seventh-inning run against Toronto reliever Casey Janssen with a two-out single to score Adrian Beltre, who doubled with one out and took third on a groundout.
"Cecil was pitching a good game, really mixing up his pitches, so going up there I really wanted to try to get a good pitch to hit before he got to his other pitches," McDonald said.
There is some personal pitching momentum and some team pitching momentum from Lester's start.
On a personal level, it follows a no-decision in the Red Sox's 4-3 victory over the Orioles on Friday, when he allowed four hits, four walks but no runs in 5 2/3 innings while striking out seven. That gives him a string of 12 2/3 scoreless innings.
It also followed the solid eight-inning outing by Clay Buchholz in Boston's 2-1 victory on Tuesday night.
"[Lester] was able to crisscross both sides of the plate," Varitek said. "He was able to throw some changeups behind in the count, some curveballs and cutters and locate his fastball. It was huge for us. Obviously we didn't swing the bats well, but we scored just enough, and it started with Jonny's pitching.
"He's been one or two pitches in each outing of going in this direction opposed to the other direction. This was a huge outing backed up by a huge outing yesterday by Clay."
"I threw a couple of good curveballs early in the count and then later in the count," Lester said. "I started to get the feel back for being able to locate my cutter down and in to some guys. [Varitek] did a good job of getting it to different spots.
"This is a great series for us. The first one was kind of weird for us, just one of those nights. We battled and were able to get the [13-12] victory, and last night, it was a well-pitched game by both sides.
"Once again we grinded it out, and that's what we did again tonight. And if we keep putting games together like that, pitching and hitting when we need to, things will take care of themselves."
The Red Sox have won five of their past six games and are now 2-7 in games when the score less than three runs. They have Thursday off before playing a three-game series in Baltimore starting Friday.
Lester is 5-3 with a 2.71 ERA in his career against Toronto.
"He pounded the zone, got a feel for his changeup early," Francona said. "He had power to his pitches. He was good. He was very good."
What was the difference between his past two starts?
"Repeating," said Francona. "After he makes a pitch, whether he misses or doesn't, he comes back with the pitch he wants to make and it looks like there was some conviction to it. That's the guy we know."
Daniel Bard came in to pitch the eighth and gave up a leadoff double to Alex Gonzalez. Then Bard, who has had trouble at times against left-handed hitters, struck out three left-handed pinch-hitters to escape the jam.
"As long as Bard makes his pitches, whether they're left or right, he's going to be OK," Francona said.
Closer Jonathan Papelbon pitched the ninth for his seventh save this season, but when he came in from the bullpen, Francona had left-hander Alan Embree, just up from Triple-A, and right-hander Ramon Ramirez warming up.
That was because Papelbon had a slightly sore back.
"We were just trying to protect our backs," Francona said. "But once he got out there, he was fine."