WASHINGTON -- Dmitri Young gave Washington's slumping offense a big boost.
Ryan Zimmerman also homered for the Nationals, who had lost seven of eight. Young added a double and finished 3-for-4, his first hits since he was selected to the NL All-Star team on Sunday.
The Nationals have struggled all season on offense. It was only the second time in 19 games they scored at least five runs. Washington hadn't scored more than three runs in 10 straight games.
"It feels good to win," manager Manny Acta said. "We know we're struggling, and when you're struggling you don't want (to prolong) the losing streak too much."
Young's grand slam capped a five-run fifth that gave Chico a 6-0 lead. Chicago, which had won three straight, lost for only the second time in 12 games.
The Cubs intentionally walked Zimmerman to load the bases and bring up Young in the fifth. Asked if that surprised him, Young just smiled.
"I was wanting them to do that," he said. "It's one of those situations where Zimmerman's been swinging a hot bat for us, and it put me in a situation (where) I actually needed to focus and try and get us some runs and I took advantage."
Chico (4-5) struck out four and did not walk a batter. Betrayed by a lack of offensive support, he was 0-1 in his previous eight starts despite giving up only 13 runs in those seven no-decisions.
Chico broke the dry spell with a strong performance. He rarely got into trouble and threw 67 of his 99 pitches for strikes.
"I expect myself to go out there and give the team a chance to win every time," Chico said. "I still have a lot to learn. Some days it falls your way, some days it doesn't."
The left-hander is the only member of Washington's rotation who didn't miss a start in the first half of the season.
Zimmerman gave Washington a 1-0 lead with a two-out homer in the first inning, and the Nationals took charge with five runs in the fifth. Jesus Flores started the rally with a single and moved to second on Chico's sacrifice. Nook Logan sent Flores to third with a single to left, and Ronnie Belliard's RBI double made it 2-0.
Chicago intentionally walked Zimmerman, loading the bases for Young, batting in the cleanup spot. He drove a 1-2 pitch from Rich Hill (5-6) into the left-field bullpen for his sixth career slam, delighting the Fourth of July crowd of 39,207.
"We tried to set up a double play," Chicago manager Lou Piniella said. "The shortstop doesn't play in the bullpen. (Young) had two strikes and (Hill) hung him a curveball."
Hill allowed six runs and 10 hits in six innings. He has lost five of his last six decisions and is winless in five outings since beating Atlanta 2-1 on June 7.
The Cubs' best scoring chance came in the eighth when they put a runner on third with two outs. But second baseman Belliard grabbed Derrek Lee's hard grounder in short right field and threw him out.
- There were 6,680 walk-up tickets sold, the second-highest amount since the team moved to Washington in 2005.
- Zimmerman also homered on July 4 last year.
- Chico got his third hit of the season, as did Hill.
- The Cubs have lost three straight July 4 games.