Jacoby Ellsbury made his first error of his Major League career, snapping club records of 232 games and 554 chances without one, but made up for it with a home run.
Dustin Pedroia, who has been struggling with the bat of late, came through with three hits, three RBIs and two stolen bases.
And the bullpen, by far the strength of the Red Sox this season, turned in four more shutout innings, with Justin Masterson, Hideki Okajima, Ramon Ramirez and Jonathan Papelbon each going one frame to preserve Penny's 100th career win.
"We're pitching, we're playing good defense, right now we're swinging the bats pretty good, too," said Pedroia. "If we keep that going, we're going to get on a little run."
The foundation has already been started. It was the sixth win in the past seven games for the Red Sox, who lead the Yankees by three games in the American League East.
"We did a good job all the way around," said shortstop Nick Green, who made a superb play in the hole to rob Hanley Ramirez of a hit in the fifth. "Brad pitched great -- he's been pitching great lately."
Penny got the job done, allowing three hits and one run -- unearned -- over five innings. The big righty walked four and struck out three, throwing 100 pitches.
Perhaps even more impressive than how Penny pitched was the way he took a shot and kept on going. To close out the first, Jeremy Hermida hit a rocket off Penny's chest that rolled all the way to first baseman Kevin Youkilis, who recorded the out.
"He got hit with that line drive smack in the chest," said Red Sox manager Terry Francona. "I don't know how he stayed in the game and pitched. He's a tough kid."
Built like a tank, Penny didn't think it was that big a deal.
"I guess it hit me in a pretty good spot," Penny said. "It hurt for a second, but after that, it didn't affect me at all."
Penny looked like he was on his way to the dugout with a scoreless first when Jorge Cantu hit a liner to left-center. Ellsbury got his glove on the ball, but he missed it. The error allowed Hanley Ramirez, who had drawn a two-out walk, to score from first.
"It's one of those things where you never want to make an error, but in baseball, it's going to happen," Ellsbury said.
But the Red Sox responded in the bottom of the second. Mike Lowell led off with a single to left, and David Ortiz continued his recent surge by belting a double off the Green Monster. That created an opportunity for Rocco Baldelli, and he cashed in, raking an RBI single to right. Boston got a second run home to take the lead on a double-play grounder by Jason Varitek.
With the bases loaded and one out in the fourth, Pedroia extended the Boston edge to 4-1 by lining a two-run single to right-center.
After going through a 2-for-28 stretch, Pedroia has started this homestand with a 5-for-10 spurt.
"I'll be fine," Pedroia said. "You go through tough times during the season when you play so hard and so many games, you're going to have tough bumps in the road, but you get back on track."
Ellsbury extended the cushion in the seventh by unloading for a solo homer to right. It was No. 3 on the season for the center fielder.
"We'll take anybody hitting a home run," said Francona. "When he uses the entire field, he's a strong enough kid where he will hit some balls out. I don't think that's what we necessarily need from him -- to be a power hitter. But I think he's going to hit some home runs."
As for the Red Sox, they continue to thrive at Fenway, where they are 23-8 this season and 327-173 (.654 winning percentage) during the sellout streak.
"I'm new here so it was a first for me to hear [about that streak]," Penny said. "That's pretty impressive. This is definitely a fun place to play."