CHICAGO -- Clayton Kershaw had his usual velocity, and that was about it. The rest of his considerable repertoire appeared in brief flashes during one of the shortest outings of his brilliant year.
A.J. Ellis and company took care of the rest.
"Obviously, you want to go eight or nine every time and be the reason why your team won," Kershaw said. "But sometimes your team does it for you and you just have to be out there. So that was the way it happened today, and I'll take it."
Kershaw (20-3) pitched five shaky innings in his shortest start in 3½ months, but the NL West-leading Dodgers roughed up Edwin Jackson on their way to a 13-hit attack that included four homers. Matt Kemp hit a three-run shot in Los Angeles' six-run first, and Yasiel Puig added another three-run homer in the sixth.
The Dodgers improved baseball's best road record to 48-31 and clinched a postseason berth when Milwaukee lost 4-2 at Pittsburgh on Friday night. They increased their lead to 3½ games over San Francisco in the division.
"We can't really worry too much about these other teams," Kemp said. "I think whatever happens, happens. But we want to win out, for sure."
Jackson (6-15) recorded just two outs in his first appearance since he was placed on the disabled list last month with a right lat strain. He was charged with four hits and five runs in his fourth consecutive loss.
"I felt good. It was just a matter of putting people away," Jackson said. "I had three ABs with two strikes on hitters and wasn't able to put them away."
Manager Rick Renteria was noncommittal when asked about the plans for Jackson for the rest of the season.
"I haven't had a conversation with anyone yet," he said.
Los Angeles batted around during its biggest first inning of the season. Kemp's drive to left was his sixth homer this month and No. 22 on the year. Juan Uribe then chased Jackson with an RBI single before Ellis went deep for his second homer of the season.
Ellis connected against Eric Jokisch again in the third for his second career multihomer game. He also had two homers against the Cubs in a 6-1 victory in Los Angeles on Aug. 3, 2012.
"He always gives you good at-bats, but you're starting to see the hits come along, too," Dodgers manager Don Mattingly said.
Anthony Rizzo had an RBI double in Chicago's three-run first, and the last-place Cubs added two more in the ninth. But that was it for Chicago in its second straight loss after a three-game sweep of Cincinnati.
Kershaw struck out nine in his sixth consecutive win. The left-hander, a prohibitive favorite for his second consecutive National League Cy Young Award, is 17-1 with a 1.39 ERA in his past 20 starts.
Kershaw had pitched at least eight innings in each of his previous seven outings. But he never looked comfortable in his second career start at Wrigley Field. He walked three, matching a season high, and hit a batter.
"It was a battle," he said. "It was just hard today."
The Dodgers have not decided on a starter for the series finale Sunday. "Every guy in the bullpen plus Danny Haren are options," Mattingly said before Friday's win.
Dodgers: LHP Hyun-Jin Ryu (shoulder inflammation) said he is feeling a lot better and hopes to begin a throwing program this weekend. The 27-year-old left-hander was removed from his start last Friday at San Francisco after just one inning and then had a cortisone shot Monday.
Cubs: C Welington Castillo was hit by a foul ball in the first and departed with a left rib contusion. The team said he is undergoing further evaluation.
Dodgers RHP Roberto Hernandez (8-11, 4.06 ERA) takes on LHP Felix Doubront (2-1, 1.50 ERA) on Saturday afternoon. Hernandez, who was acquired last month in a trade with Philadelphia, is 1-1 with a 3.27 ERA in two starts this year against Chicago. Doubront pitched six scoreless innings in a 6-4 victory at Pittsburgh in his previous start last Saturday.