CHICAGO (AP) Looking quite comfortable in the middle of the order, Ben Zobrist is benefiting from the relentless approach by the Cubs' dangerous lineup.
Zobrist went 4 for 4, Addison Russell had three RBIs and Chicago beat the San Diego Padres 8-7 on Tuesday night for its eighth straight win.
''You pass the baton,'' Zobrist said. ''That's what we try to do in the lineup, and guys have been doing a good job of that.''
Jon Lester (4-1) pitched six innings of three-run ball as Chicago improved to 25-6 for the best start by a major league team since the 1984 Detroit Tigers won 26 of their first 31 games. Kris Bryant drove in two runs and Jason Heyward scored twice, helping the Cubs open an 8 1/2-game lead over second-place Pittsburgh in the NL Central.
Zobrist had run-scoring singles in the third and fourth against rookie Cesar Vargas (0-2). Zobrist also singled in the second and seventh, and scored in each inning on a hit by Russell.
''I feel like it's a cumulative effect for the whole team,'' Zobrist said.
''Obviously they're not getting breaks in our lineup and that's what makes it so difficult for them to stay focused on every hitter.''
Zobrist, a switch-hitter who signed a $56 million, four-year contract with Chicago as a free agent, is batting .365 (23 for 63) with 23 RBIs in his last 18 games. He has driven in 17 runs during Chicago's win streak.
''I've seen Zo really good,'' said Joe Maddon, who also managed Zobrist with Tampa Bay, ''and he's really good right now.''
Alex Dickerson became the first player in Padres history with a pinch-hit grand slam for his first career homer, according to STATS, but San Diego lost its third consecutive game. Melvin Upton Jr. also went deep for the Padres, and Jose Pirela had two hits and scored two runs.
''A special moment for me and all the work I've put in to this point,'' Dickerson said.
San Diego lost another infielder when shortstop Alexei Ramirez left in the fifth inning due to cramping in his left hamstring. After hustling into second with a run-scoring double, Ramirez was hunched over behind the bag when a trainer came out to check on him.
Ramirez motioned to his hamstring and walked off the field under his own power after a short discussion. The Padres had nine players on the disabled list coming into the day, including four infielders.
''He tells me right now he's feeling fine,'' manager Andy Green said. ''You can imagine with the rash of hamstring injuries and quad injuries we've had, if somebody says, `My hamstring hurts,' we're going to be very cautious. He was upset that we took him out and thought he was fine to play through it.''
Dickerson's drive on an 0-2 pitch from Adam Warren trimmed Chicago's lead to 8-7 with two outs in the eighth. But Jon Jay bounced to second to end the inning, and Hector Rondon got three outs for his seventh save in seven chances.
GUTTING IT OUT
Lester allowed four hits, struck out four and walked one. It was his first win in three career starts against the Padres.
''We had to kind of invent ways to get guys out tonight,'' he said. ''Didn't really have anything.''
The Padres claimed left-hander Keith Hessler off waivers from the Diamondbacks. Green said Hessler could be added to the roster as the 26th player for Wednesday's doubleheader against the Cubs.
Padres: LHP Matt Thornton (Achilles) is scheduled to throw a live batting practice session Wednesday in Arizona. ... 2B Jemile Weeks (hamstring) was scheduled for an MRI on Tuesday. He was placed on the disabled list Sunday.
Cubs: C Miguel Montero (lower back tightness) began a rehab stint with Triple-A Iowa. The length of his rehab period depends on how he feels, according to Maddon. ''Whatever his body tells him, we'll follow that direction,'' Maddon said.
The Cubs and Padres make up Monday's rainout when they play a day-night doubleheader on Wednesday. RHPs Kyle Hendricks (2-2, 3.10 ERA) and John Lackey (4-1, 4.02 ERA) go for Chicago, and San Diego sends RHP Colin Rea (3-1, 3.82 ERA) and LHP Drew Pomeranz (3-3, 2.12 ERA) to the mound. The Cubs haven't won a home series against San Diego since they swept a three-game set in 2012.
Jay Cohen can be reached at http://www.twitter.com/jcohenap