The team turned a season-high four double plays to complement a solid 13-pitch relief outing from Chris Sampson.
Sampson entered the game with the bases loaded and one out in the sixth inning, and his first pitch slipped away to hit Jesus Flores in the shoulder.
As power hitter Wily Mo Pena came up to the plate, Sampson concentrated on forcing the ground ball and cleanly fielded a comebacker to the mound to begin a 1-2-3 double play that ended the inning.
"Getting that double-play ball with the bases loaded was huge," first baseman Lance Berkman said. "Chris did a great job making a pitch to a guy who has a lot of power. That could have gone against us, but we made that pitch and got out of it."
It was just one more example of the solid defense that helped starter Wandy Rodriguez make it through 5 1/3 innings of work.
"The guys got me out of a lot," Rodriguez said. "And to have the run support, I'm very happy."
Houston's bats put the game out of reach in the fifth inning. After Darin Erstad reached on an error, doubles from Kazuo Matsui and Berkman set the tone, and the inning was extended when Nationals first baseman Paul Lo Duca, usually a catcher, forgot he could tag Carlos Lee for the inning's third out after catching a line drive. Lee made it back to the base, and the team punched out two more hits before Nationals pitcher Collin Balester was removed from the game.
Balester, in just his third Major League start, had to stare down a lineup of veteran hitters who seemed to be in tune with the rhythms of his fastball and changeup. Those hitters were also licking their chops after a 10-0 loss on Friday night.
"You can tell he's going to be a great pitcher in this league; we just happened to find some holes when it counted," right fielder Hunter Pence said. "Nothing got running for us yesterday, and then it seemed to happen today. That's baseball."
Pence contributed with a home run in the fourth inning, taking a 90-mph fastball above the left-field wall at Nationals Park. He finished with two hits and three RBIs.
The offense was led by Lee, who singled three times. In the seventh inning, he hustled out a ground ball to shortstop, making it to first base in time but also grimacing, prompting a visit from the team trainer. He remained in the game, substituting out for a defensive replacement in the bottom of the ninth.
Lee's hustle on the grounder was the sort of effort that made the difference against a shaky defense. Berkman said that the team's hustle is always more visible in a winning effort.
"Everything looks great when you score six runs and win the ballgame," Berkman said. "Guys played just as hard when we lost 10-0, but winning covers a multitude of evils and makes you look good."
Manager Cecil Cooper gave his praise to the pitching staff, including Rodriguez, Sampson, Geoff Geary and closer Jose Valverde, who picked up his 24th save. Rodriguez left the game having thrown 80 pitches.
"[Rodriguez] gave up a couple leadoff doubles, but was able to limit the damage," Cooper said. "He got the double-play balls, which is what you have to do to keep those crooked numbers off the scoreboard."
The Nationals picked up a home run and a double from Willie Harris, and two hits each from Ronnie Belliard and Lo Duca.
With one more game before the All-Star break, the Astros want to bring back the team that scored six runs and turned double plays on Saturday, instead of the one that lost by 10 runs on Friday.
"We've got to continue to battle," Pence said. "If we do those little things right, we'll win more ballgames."
Michael Phillips is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.