Dansby Swanson hit a three-run double in a five-run second inning and the Braves held off the St. Louis Cardinals 6-3 early Tuesday in a game delayed more than 2 1/2 hours by rain.
Swanson's bases-loaded double was the big hit against Dakota Hudson (6-5) in the second. Swanson also doubled and scored in the first.
Swanson was hitting only .236 on May 23. Since then, he has the most hits in the majors while raising his batting average to .304. His 37 hits in June were the most by a Braves shortstop in a month since Omar Infante's 43 in August 2010.
The surge has come as Swanson is approaching possible free agency while being represented by the same Excel Sports Management, including agent Casey Close, used by former Braves first baseman Freddie Freeman.
Freeman signed with the Los Angeles Dodgers after he was unable to reach agreement on a deal with Atlanta.
Swanson, 28, hit only .248 but set career highs with 27 homers and 88 RBIs while helping Atlanta win the World Series last season.
The Braves (47-34) went 21-6 in June after finishing May at 23-27.
Matt Olson had two RBI singles for Atlanta, driving in Swanson both times.
There was a delay of 2 hours, 37 minutes, before the matchup of second-place teams resumed in the fifth inning at 11:29 p.m.
The Braves remained 3 1/2 games behind the first-place New York Mets in the NL East. The Cardinals fell three games behind division-leading Milwaukee in the NL Central.
Atlanta right-hander Jesse Chavez (2-1) gave up homers to rookies Juan Yepez and Conner Capel in the sixth. Capel's homer to center field was the first of his career.
Hudson allowed six runs on nine hits and three walks in four innings.
St. Louis right-hander Johan Oviedo left the game after a line drive hit by Michael Harris II struck Oviedo's right hand in the sixth. The Cardinals said X-rays were negative.
After scoring one run in the first when Olson's single drove in Swanson, the Braves sent nine batters to the plate in the second. Ronald Acuna Jr. drove in a run with a bases-loaded walk after Hudson hit Harris with a pitch.
With three runners on the move on a full-count pitch, Swanson's double to left-center made it 5-0. Olson's second run-scoring single pushed it to 6-0.
Eddie Rosario, who had laser surgery to correct blurred vision and a swollen right retina, came off the injured list and had one hit while starting in left field for Atlanta.
Braves RHP Ian Anderson (6-5, 5.31 ERA), who has allowed a combined 11 runs in losing his last two starts, will face Cardinals rookie RHP Andre Pallante (2-3, 2.10) on Tuesday night. Anderson will be making his first career start against St. Louis.