Over 6 1/3 innings, Doubront allowed just three hits and two runs, one of which was earned. He walked three and struck out five.
Such work has become the norm for the emerging southpaw from Venezuela.
"As we've seen over the last 11 times he's gone to the mound for us, he's working six or seven innings each time out," said Red Sox manager John Farrell. "Low runs. And then probably the last five or six of those starts, he's come out and gotten into the rhythm of the game much earlier than maybe the first month and a half of the season. He kept the game in check. Another very solid outing on his part."
After being dealt some bad news before the game -- reliever Andrew Bailey could be out for the season -- another strong performance by Doubront was something for the Red Sox to enjoy in their first game coming out of the All-Star break.
"I keep going deep in the game," said Doubront. "And my confidence, my focus is improving. I'm just trying to go deep and help the team win the game, keep the score down and let my team score runs."
With a win in their first home game against the Yankees this season, the Red Sox maintained their 2 1/2-game lead over the Rays in the American League East.
"Every game is important for us," said second baseman Dustin Pedroia. "We're just trying to play the best we can and win as many ballgames as possible, because we know in the end, everyone is right there."
By allowing three earned runs or fewer for the 12th straight start, Doubront improved to 7-3 while lowering his ERA to 3.76. Over that 12-start span, he has a 2.59 ERA.
In six career starts against the Yankees, Doubront is 3-1 with a 2.17 ERA.
"He's throwing well," credited Yankees manager Joe Girardi. "You look at the last two months, he's pitched extremely well since the end of May. He's been tough on us. He has a very good changeup. We know that."
This time, Doubront outpitched one of the most accomplished pitchers in the game in Andy Pettitte.
The Red Sox generated just enough offense to hand the loss to the venerable lefty, who gave up six hits and four runs over 6 1/3 innings on a sweltering evening at Fenway.
Jacoby Ellsbury gave the Red Sox a quick burst of offense in the bottom of the first when he led off with a homer that soared over the Yankees' bullpen and into the bleachers.
Pettitte was solid for most of the night, but he did run into some early trouble. Mike Napoli led off the second with a walk and Jonny Gomes followed by drilling a two-run shot over the Green Monster, giving Boston a 3-0 edge.
"Ells kick-started us," said Gomes. "One to nothing [after the] first batter.
"It's definitely not a guessing game [with Pettitte]," Gomes continued, "but you kind of got to put your chips on two of his three pitches. [The home run] wasn't a bad pitch, but I hadn't seen his changeup yet, thought he was going to throw it, and [it] worked out."
Doubront kept it right there until the fourth. Brett Gardner, who would later be ejected, stole second to put himself in scoring position. When he stole third, Jarrod Saltalamacchia's throw went into left field, and Gardner easily scored.
Lyle Overbay led off the fifth with a double and Chris Stewart lofted a two-out RBI double to left to make it a 3-2 game.
Gomes gave Boston another important hit to lead off the seventh, looping a ground-rule double down the line in right. With two outs, Jose Iglesias came through with a clutch RBI single to right against righty Shawn Kelley, giving Boston's bullpen a little breathing room.
Craig Breslow pitched around a two-on, one-out jam in the eighth, and Koji Uehara retired the Yankees in the ninth for his ninth save of the season.