ATLANTA — Everything was in place for Shelby Miller to end his frustrating winless streak. And then everything fell apart in the seventh inning.
Miller's winless streak reached 18 games, the longest in-season streak for a Braves pitcher since the team moved to Atlanta in 1966.
"Those are the type of games you like to have Shelby in there," Braves manager Fredi Gonzalez said. "You're up 3-0 and you run him back out there, you feel pretty good."
Miller had set down 14 straight Rockies entering the seventh inning and seemed poised to record his first win since May 17. But he gave up a double to Ben Paulsen, a single to Daniel Descalso and a double to Barnes that cut the deficit to 3-1. Charlie Blackmon hit a two-out infield chopper to make the score 3-2 before Jose Reyes launched a triple to right-center to score Barnes and Blackmon.
"That was some bad luck," Gonzalez said. "He made a nice pitch to Blackmon. The ball hit off the plate."
Barnes tacked on a two-run homer in the eighth off Edwin Jackson to push the lead to 6-3.
The Braves threatened in the late innings, loading the bases in the seventh and getting two men on in the ninth, but the Rockies' bullpen managed its fourth straight scoreless game. John Axford struck out Pedro Ciriaco to earn his 18th save.
Simon Castro (1-0) picked up the win in relief for the Rockies, who won two out of three for their first series win at Turner Field since 2005.
During his winless streak, Miller has an ERA of 3.24 and has given up one earned run or less eight times. He broke Nolan Ryan's record of longest winless streak by an All-Star, which was 13 starts.
"Everyone knows it's going on," second baseman Jace Peterson said of the streak. "It is one of those things that's terrible, but I know we are going to keep battling."
The Braves got on the board on an RBI groundout by rookie Christian Bethancourt in the second inning that scored Gomes.
Rockies: OF Carlos Gonzalez returned to the lineup after missing Tuesday's game with a sore knee. ... 3B Nelson Arenado was a healthy scratch.
The Rockies will have a day off Thursday and open a three-game series at Pittsburgh on Friday. Rookie Jon Gray (0-0, 5.94) will start for the fifth time since being called up from Triple-A Albuquerque on Aug. 4. The Pirates will start Francisco Loriano (9-6, 3.23), who is 1-2 with a 5.48 ERA in four career starts against the Rockies.
The Braves will host the Yankees for a three-game series starting Friday. This is the Yankees' first visit since 2012 and the crowds are expected to be large at Turner Field. Braves rookie Williams Perez (4-4, 4.76) will face Masahiro Tanaka (9-6, 3.61) in the opener.
Due to a defensive shift, Atlanta's Freddie Freeman grounded into a rare 6-5-3 double play in the first inning as SS Reyes was playing to the right side of second base and 3B Descalso made the pivot at second.
Garcia made three errors at third base during Tuesday's loss to the Rockies, but he rebounded Wednesday with three hits, including a home run, and no errors.