Three straight losses to Atlanta provided more evidence of the improvement needed from the weak-hitting Cubs.
Chicago had 14 strikeouts and came up empty too often in key situations in its 5-2 loss to the Atlanta Braves on Sunday.
The Cubs began the day in the National League's bottom three in hitting and runs scored. Chicago was held to four runs as the Braves swept the three-game series.
On Sunday, Cubs hitters were 1-for-8 with runners in scoring position and left eight runners on base.
Manager Rick Renteria said hitting coaches Bill Mueller and Mike Brumley are trying to change the way their hitters approach different situations, including at-bats with runners in scoring position.
"That's something that's ongoing," Renteria said. "I think that all the guys are, hopefully, learning from all these experiences, because we've got to take something away that will help us down the road. We've got to keep plugging ... do a better job of understanding the situation, not getting ourselves too excited."
Ryan Kalish, Chris Coghlan and Wellington Castillo each had two strikeouts against Aaron Harang (4-3). Among NL teams, only the Marlins have more strikeouts than the Cubs' 341.
"They have a young, aggressive team over there and I think I was able to take a little advantage of that, knowing how aggressive they are," Harang said.
The Cubs, last in the NL Central, have dropped seven of eight.
Harang pitched six strong innings and was backed by home runs from Evan Gattis and Jason Heyward.
Gattis gave Atlanta a 3-2 lead with his homer off Edwin Jackson in the fourth inning. Heyward added to the lead with his first home run since April 9, a seventh-inning, two-run drive off James Russell that landed in the Braves' bullpen beyond the right-field wall.
"It felt like it was longer than that," said Heyward of the power drought.
"I keep on showing up every day and trying to put up good at-bats and find good pitches to hit. If you try and do too much, that's when you start to compound things."
Jackson (2-3) allowed three runs on six hits and two walks in six innings.
"The two balls I got hurt on were balls up and over the middle," Jackson said. "Balls that should be hit. I've just got to do a better job of getting ahead in the count and working down."
David Carpenter pitched the ninth for his second save. B.J. Upton made a sliding catch of Ryan Kalish's short fly in center field to end it.
Atlanta closer Craig Kimbrel was rested after pitching two straight days.
The NL East-leading Braves have recovered from seven straight losses by winning four of five. Ryan Doumit had a run-scoring single and Andrelton Simmons drove in a run with a double to give Atlanta a 2-0 lead in the second.
The Cubs tied it in the fourth on Nate Schierholtz's two-run double.
The Braves quickly reclaimed the lead when Gattis hit his eighth homer over the 380-foot sign in left field.
Dan Uggla was hit by a pitch from Russell as a pinch-hitter to lead off the seventh. Uggla scored on Heyward's third homer.