CHICAGO -- Chris Capuano beat the Chicago Cubs with his bat and his arm on Saturday. Guess which one he'll remember more?

Capuano threw seven shutout innings and drove in two runs to lead the Los Angeles Dodgers to a 5-1 win over the Cubs.

Capuano (4-0) held Chicago to three hits and struck out seven, extending his scoreless innings streak to 18 2-3. His two-run double in the second gave him his first RBI since Aug. 24, 2007.

"The first thing I did when I came in was watch my hit about 10 times," Capuano said. "That's the thing we get excited about as pitchers."

There are plenty of reasons to be excited for the first-place Dodgers, who avoided their first three-game losing streak of the season. It's just the second time since 1988 that Los Angeles has won at least 18 of its first 27 games.

"It's been a lot of fun," Capuano said. "We've got great chemistry in the clubhouse. We're really staying together. As long as we continue to do that, it should be a fun year."

Los Angeles started 19-8 in 2009, the last year the Dodgers won the NL West.

Cubs starter Chris Volstad (0-4) fell to 0-9 over 17 starts dating to July 10. He allowed four hits and five runs over five innings, walking three and striking out one.

During Volstad's long winless streak, his Achilles' heel has been an inability to avoid big innings. The problem surfaced again on Saturday when his leadoff walk to Andre Ethier in the second led to a sacrifice fly.

Later that inning, Volstad left a pitch up to Capuano, who laced it into the gap in right-center for a two-run double.

"Big one of the game," Volstad said. "Second and third, nobody out, giving up one run I'd be feeling pretty good, the team's still in the game. He hit that ball really well."

Capuano, who was a capable hitting pitcher before missing two seasons with an elbow injury, had gone just 5 for 79 without an RBI since returning to the majors in 2010.

Capuano is off to his best start since winning his first five decisions in 2007. He's hoping this season turns out better after he lost his final 12 decisions that year. The lefty has won seven of his last nine starts against the Cubs, who barely threatened him on Saturday.

"I added a breaking ball in spring training that's been helping me out and that I have a pretty good feel for," Capuano said. "It's good having a couple of more weapons out there."

Chicago loaded the bases with one out in the first, but Capuano struck out Alfonso Soriano and Ian Stewart looking. The Cubs got just three base runners against Capuano over his last six innings and didn't get another runner past first base.

"I was pumped up getting that last out," Capuano said. "I think it kind of helped the momentum swing our way. That's always big, when you can get out of a jam early."

Starlin Castro singled three times for the Cubs, but committed his eighth error, the most in the majors.

Matt Kemp went 0 for 3 but drove in a run with a sacrifice fly in the fifth.

Kemp's batting average dropped below .400 for the first time since April 10. The major-league home run leader hasn't gone deep in the Dodgers' last four games, his longest drought of the season.

Dee Gordon doubled home Matt Treanor in the fifth. Gordon also singled and stole his 12th base of the season.

"We just kind of chipped away," Dodgers manager Don Mattingly said. "We didn't do a ton, but we did enough to get comfortable."

• Volstad started in place of Matt Garza, who is battling a virus. Garza's start was pushed back to Sunday, though Cubs manager Dale Sveum said that possibility is "pretty iffy." Garza's start may be skipped altogether. If Garza can't pitch Sunday, LHP Travis Wood will be recalled from Triple-A Iowa to take his turn in the rotation. Wood was in the Cubs' clubhouse on Saturday.
• Sveum said that utility player Jeff Baker has the same illness as Garza and was unavailable for Saturday's game.
• LHP Ted Lilly was ejected from the Dodgers' dugout by home plate umpire Tim Timmons during the top of the fifth.