WASHINGTON -- Washington's talented rotation has overshadowed its lineup for most of the season.
It turns out the NL East leaders can hit, too.
LaRoche and Jayson Werth had four hits apiece for the Nationals, who opened a season-high 7 1/2-game advantage in the division. Second-place Atlanta lost to Colorado 6-0.
"We owe this to our pitchers for bailing us out," LaRoche said.
"It goes back to getting a lot of guys going well. You see better pitches. Everybody gets better pitches to hit. There's nobody to really pitch around because you get somebody dangerous on deck."
Werth and Michael Morse missed substantial time this season because of injuries, and Desmond was out for 3 1/2 weeks with an oblique strain. The Nationals have had all three together since Aug. 17.
"We're in a pretty good place offensively," manager Davey Johnson said. "I like the lineup we have. We haven't had the lineup together very long."
Nationals right-hander Edwin Jackson (9-9) allowed four runs and seven hits in 5 2/3 innings. He struck out eight and walked one.
Washington has scored 19 runs in Jackson's last two starts.
"There's definitely nobody in the clubhouse that's going to complain about run support," Jackson said.
Desmond hit a two-run drive off Chris Rusin (0-2) in the first for his 20th homer. The All-Star shortstop added a two-run double in Washington's three-run second.
Rusin, who was recalled from Double-A Tennessee before the game, was pulled after the first four batters reached in the second. He was charged with five runs and eight hits in the Cubs' shortest start of the season.
"Without breaking balls you better keep it down and you better have movement and today he didn't have either," Cubs manager Dale Sveum said.
"The cutter wasn't doing a whole lot and you couldn't get the ball to sink or keep it down. He threw a few good changeups, that was about it. It's tough to get through a major league lineup, let alone that lineup, with a flat fastball."
Chicago used seven pitchers, five in the first five innings.
"Always a chance to make an impression. That's what you want to do, but you can't have outings like this," Rusin said.
LaRoche had a solo shot and Moore belted a two-run drive off Rafael Dolis in the fourth. Zimmerman led off the sixth with his 18th homer off Miguel Socolovich and LaRoche connected for his 27th homer against Jeff Beliveau in the eighth.
"We know we're capable of hitting the ball out of the ballpark," Desmond said.
The Nationals are third in the NL with 151 home runs.
"The offense was fun to watch," Johnson said.
Chicago has eight losing streaks of at least four games this season.
The Nationals also hit six home runs on May 20, 2011, in Baltimore. ... RHP Jaye Chapman, who also was recalled from Double-A Tennessee on Tuesday, Socolovich and C Anthony Recker made their Cubs debuts. Chicago has used 29 pitchers and 52 players, both franchise records. ... Washington activated RHP Chien-Ming Wang, who had been on the 15-day disabled list since July 1. The Nationals also recalled OF Corey Brown from Triple-A Syracuse. ... Washington RHP Christian Garcia made his major league debut, retiring the only batter he faced in the sixth inning. ... NASCAR driver Kurt Busch threw out a ceremonial first pitch. ... Washington LHP Gio Gonzalez (17-7, 3.10 ERA) will face RHP Chris Volstad (2-9, 6.06 ERA) when the series resumes on Wednesday.