"I don't know if it's about getting in their heads," Freeman said. "You just want to go out there and win series. It doesn't matter who it's against."
Beating Washington for the 18th time in the last 25 series matchups, Atlanta is hoping to use another fast start against the Nationals to win a second straight NL East title.
The Braves have won five of six against the Nationals this year.
"We have a 19-game stretch against division opponents," Freeman said. "This is where you can get off to a good start and get off to a good lead and hopefully we'll keep playing well when we get to" Philadelphia to begin a four-game series Monday.
Washington began the day by placing third baseman Ryan Zimmerman on the 15-day disabled list with a broken right thumb. He'll be out four to six weeks.
Gonzalez (2-1) continued his struggles against the Braves, giving up nine hits, six runs and four walks and striking out six in six innings.
Despite ranking second in the majors among left-handers with 34 wins since the start of 2012, Gonzalez is 2-7 with a 5.31 ERA in 10 starts against the Braves during that span.
He hasn't received more than one run of support in any of his seven winless starts against Atlanta.
"We were catching bad breaks," Gonzalez said. "We were making some big mistakes, and as a starting pitcher you've got to learn to adjust and keep the ball down."
Harang, making his 322nd career start and third with the Braves, improved to 2-4 with a 3.72 ERA in 10 starts against Washington.
Gonzalez's struggles began in the first.
After walking leadoff hitter Jason Heyward, Gonzalez made an errant underhanded throw to first baseman LaRoche on B.J. Upton's bunt single. The ball rolled away from LaRoche, allowing Heyward to advance to third and B.J. Upton to second.
Freeman's sacrifice fly scored Heyward, and Justin Upton homered to make it 3-0. Over his last six games, Justin Upton is hitting .590 with four homers in 22 at-bats.
"We know what we're capable of and what we want to achieve," Justin Upton said. "If everybody can contribute every day, I think we'll be fine."
Atlanta added three more runs in the second.
Tyler Pastornicky led off with a triple and scored on Heyward's RBI double. Freeman followed with his fourth homer to give the Braves a 6-0 lead.
Freeman, who has hit .470 in his last 34 at-bats, avoided a scare in the fourth when Gonzalez's 92 mph fastball hit the outer right side of his right hand. Like the rest of the day, everything seemed to go Atlanta's way.
"It pinched my pinkie into the bat," Freeman said. "It was more a scare than an injury. I got really lucky. I think if I didn't choke up, I'm done. By choking up, it got some fat right there. I kind of lucked out, I think."
Washington RF Jayson Werth returned after a sore groin forced him from the lineup on Saturday. Werth went 0 for 4 with two strikeouts and stranded three runners. ... Simmons hit in the No. 5 spot for the first time in his career, going 2 for 5 with three RBIs. ... Nate McLouth was supposed to start in CF and bat second for Washington, but manager Matt Williams said he tweaked his left knee while shagging flyballs during batting practice and was held out. ... Nationals LF Steven Souza Jr. made his major league debut in the seventh as Frandsen moved to second base and Danny Espinosa left the game. Souza struck out in the eighth. ... The Nationals called up INF Zach Walters from Triple-A Syracuse to take Zimmerman's spot on the 25-man roster. Walters struck out as a pinch-hitter to end the game. ... Span, on the seven-day DL with concussion symptoms, missed his second straight game.