ATLANTA - Manager Fredi Gonzalez knows the Atlanta Braves don't have much margin for error these days. The offense, starting pitchers, bullpen and defense rarely seem to be in sync.
That certainly was the case when second baseman Jace Peterson's throwing error led to a pair of unearned runs against starter Shelby Miller.
"Not only did it cost us two runs, but it was also an extra 10 or 12 pitches that he's got to throw to get out of that inning," Gonzalez said. "Instead of going six innings, he could've probably gone seven or worked a little less than he did."
A 4-1 loss to the Chicago Cubs on Sunday was the Braves' seventh defeat in eight games. Atlanta is a season-worst six games under .500 and seven games back in the NL East.
Jake Arrieta pitched seven dominant innings and Jorge Soler homered to help the Cubs win a series at Turner Field for the first time since Aug. 12-14, 2011.
Arrieta (11-5) gave up three hits, three walks and struck out 10, throwing 73 of his 112 pitches for strikes. Over his last six starts, the right-hander is 5-0 with a 0.96 ERA.
It was the second straight impressive start for the Cubs, whose starting pitchers have a 1.29 ERA over their last 16 games. Jon Lester gave up just two hits and one walk in 7 1/3 innings of a 4-0 win Saturday.
Miller (5-6) struck out eight and allowed four hits, four walks and three runs - one earned - in six innings for the Braves. He is winless in last 11 starts despite a 3.15 ERA during that stretch.
"I made a bad pitch (to Soler) and ended up giving up two runs (to Herrera), but other than that and the homer, I felt good," Miller said. "It's unfortunate that we lost. Physically, I felt good."
After James Russell walked Perez with two outs in the ninth, closer Jason Motte gave up Andrelton Simmons' RBI single to make it 4-1, but he retired pinch-hitter Jonny Gomes on a groundout in a non-save situation.
Simmons snapped a 17-inning scoreless streak for the struggling Braves.
Arrieta, who set a career high in victories, had to grind through a tough seventh, but after Eury Perez doubled with two outs and Simmons walked, pinch-hitter Joey Terdoslavich struck out to end the threat.
The Braves seemed helpless to solve Arrieta, who allowed two walks and had both runners in scoring position in the first before escaping the jam with a strikeout of A.J. Pierzynski.
Pierzynski, who broke up Lester's bid for a no-hitter Saturday with an eighth-inning single, doubled with two outs in the fourth for Atlanta's first hit, but Arrieta struck out Pedro Ciriaco.
Cameron Maybin's one-out single in the sixth was harmless, too, as Arrieta stranded him by striking out Kelly Johnson.
"We've talked about him being one of the elite pitchers in the National League," Cubs manager Joe Maddon said, "and he proved it again today."
The Cubs went up 2-0 in the second. Chris Coghlan singled and moved to second when Starlin Castro reached on Peterson's throwing error. After a walk to David Ross loaded the bases, Jonathan Herrera hit a two-run single to center field.
Peterson blamed himself for hurting Miller's chances to win.
"I thought he did everything he could," Peterson said. "Unfortunately, I didn't make a play behind him, and I think in this situation it cost us."
Soler hit his fifth homer to make it 3-0 in the third. It was Soler's first homer since May 29 against Kansas City.
Coghlan's RBI double in the ninth put the Cubs ahead 4-0.
Pedro Strop pitched the eighth for Chicago, giving up a leadoff double to Peterson but stranding him at second.