Bryce Harper singled in the first, stole second, advanced to third on a throwing error and scored on Ryan Zimmerman's groundout to give his starter the lead before he even had to throw a pitch.
Zimmermann (4-6) coasted from there. A Marco Scutaro single in the third scored the only run he allowed in seven innings of work. The righty scattered eight hits, using four double-play ground balls to avert trouble.
"Zim was outstanding," Nationals manager Davey Johnson said. "A lot of his breaking balls were up, but he made quality pitches when he had to."
A night after scoring 12 runs in a victory, Washington double-dipped again -- the third time in Nationals history since moving to Washington in 2005. Each of the club's starting hitters got on base and the only one who didn't get a hit, Mark DeRosa, made up for it by drawing two walks, scoring two runs and lifting a sac fly in the seventh inning.
The Nationals tore through two Rockies pitchers in the span of three innings, pegging Edwar Cabrera for seven runs -- five earned -- in 2 1/3 innings of work. Cabrera, making his Major League debut, gave up three homers.
"At one point he had something like three out of 14 hitters with first-pitch strikes," Rockies manager Jim Tracy said. "That's not a good place to be in your Major League debut."
After Cabrera was pulled, Matt Reynolds came on to get the last two outs of the third. The lefty gave up two hits and one run in the process.
It was not lost on the Nationals that this production is coming in a hitters park, against a Rockies team that is dead-last in the Majors in nearly every major pitching category. But they'll take a shot of confidence any way they can get it, especially with a series against second-place Atlanta looming this weekend.
"To get back-to-back nights like this and build some momentum going into the second half of the season is huge," said third baseman Ryan Zimmerman, who hit a home run for the second straight game and finished 2-for-4.
Many club records for offense were tied or shattered on Tuesday. While the Nationals didn't enjoy as prolific a night -- the 11 runs were only second-most on the year, the 14 hits were only tied for fourth-most -- it was perhaps a more important win, one that gives them the best record in the National League (43-30) and helps maintain a 3 1/2 lead in the NL East.
And it was important to show the league, and themselves, that Tuesday's output was no fluke.
"Sometimes that does happen, [Tuesday] night was pretty amazing," said Tyler Moore, who slugged his second home run in the last two games. "But it was pretty cool to see this back-to-back."
Entering Tuesday's game, Washington averaged the fourth-fewest runs-per-game output in the National League, with 3.73. The Nats still rank in the bottom half of the NL when it comes to most offensive categories, but they're slowly creeping up the charts. They had the third-lowest cumulative batting average on Monday -- now they have the fifth-lowest. Twenty-three runs in the span of two games will do that for you.
"The offense has been maligned and everything else," Johnson said. "But we have the potential to be a really good offensive ballclub."