ATLANTA -- The Chicago Cubs were a comedy of errors defensively with Bill Murray on hand for the final two games against the Atlanta Braves at Turner Field.

The Cubs won both in laughers anyway, making the actor-comedian happy and improving the team's major league-best record to 43-18.

Jon Lester didn't allow an earned run over seven innings in winning his fourth straight start and the Cubs overcame four errors in the first two innings with a 13-2 pounding of the Braves on Sunday. Chicago had three errors Saturday.

"It was uncharacteristic," Cubs manager Joe Maddon said of the miscues. "We made some mistakes, no question about it. But at no time did I feel that it got to us or dragged us down. ... And the big part was Jon."

Lester (8-3) allowed five hits and an unearned while striking out seven and walking none as he improved to 4-1 for his career in Atlanta. He also squeezed in a run.

"He was on top of his game. He's really pitching with a lot of confidence right now," Maddon said.

It was the third straight game that Lester didn't walk a batter and he has 26 strikeouts to no free passes over 24 innings in June.

"I don't think I've ever gone this many starts in a row, probably this many in a season, without walking somebody," Lester said.

The no walks helped mitigate the Cubs' early defensive struggles and then the bats came alive late.

"You can't really worry about [errors]," Lester said. "Guys are obviously not trying to make errors, so it is my job to pick them up. They pick me up more times than not."

Anthony Rizzo had three hits and three RBIs, while Javier Baez blasted a three-run homer as part of a six-run eighth inning that followed a three-run seventh by the Cubs.

Jason Heyward had three hits and scored three times, and David Ross, who made two of the Cubs' errors, joined Ben Zobrist with two hits and two RBIs.

"The Cubs are a great team. There is a reason they've won 43 games," Braves outfielder Jeff Francoeur said. "After we won Friday's game, we knew it would be tough the next two days. This one kind of got out of hand."

Atlanta has the worst record in the majors at 18-44, including 7-25 at home.

It was the Cubs' last game at Turner Field, where they won their first postseason series since 1908 by taking a deciding Game 5 of the 2003 National League Division Series. The Braves move to a new suburban stadium in 2017.

Rizzo followed a pair of walks by rookie Atlanta right-hander John Gant with an RBI double in the first, but the Braves answered with an unearned run in the bottom of the inning thanks to a throwing error by catcher Ross on a double steal.

Lester pitched around throwing errors by second baseman Zobrist and Ross on the same play in the second inning and then squeezed in one of the Cubs' two runs in the fourth to go ahead for good.

The Cubs had two hits and a walk in the inning, with the first run scoring when right fielder Nick Markakis booted a single by Ross and the second coming on a squeeze bunt by Lester.

Gant (0-1) allowed three runs (two earned) and four hits over 4 1/3 innings in his first major-league start after seven relief appearances. He walked four and struck five.

"I was pleased to get the start," Gant said. "Obviously, you can't be pleased with the loss."

The Cubs pushed their lead to 4-1 in the sixth inning off reliever Casey Kelly as Ross followed a double by Chris Coghlan with an RBI single. Then they broke things open in the seventh with three runs, all charged to Kelly.

Rizzo drove in the first with a single and Zobrist delivered the second with a double. Alexei Ogando walked Ross with the bases loaded to force in the final run of the inning.

The Cubs added six runs in the eighth off Chris Withrow, capped by Baez's three-run homer. Rizzo, Zobrist and Albert Almora Jr. had RBIs singles before Baez hit his fifth homer.

Francoeur had an RBI single for the Braves in the eighth inning off Adam Warren.

Maddon got a chance to spend time with Murray after Saturday's game.

"He's easily very funny, a naturally very funny guy," Maddon said. "He wanted to know about [my hometown of] Hazleton [Pa.] last night, so I gave him a rundown. Whenever the opportunity popped up for him to say something clever, he did."

NOTES: The Braves activated SS Erick Aybar (right foot contusion) on the first day he was eligible and put the veteran back in the starting lineup. He was hit by a pitch May 27 against Miami and had played seven rehab games with Triple-A Gwinnett. ... To make room for Aybar, the Braves optioned INF Daniel Castro to Gwinnett. Castro had started games at shortstop, second base and third base, but his batting average was down to .182 in 42 games. ... The Cubs open a three-game series in Washington on Monday, with RHP Kyle Hendricks (4-5, 2.90 ERA) starting the opener against the Nationals. ... Rookie RHP Aaron Blair (0-4, 7.13 ERA) will start Monday for the Braves against Cincinnati to begin a four-game home series.