Donovan Solano provided the decisive hit, lining a pinch-hit RBI single in the ninth inning off Craig Kimbrel to lift the Marlins to a 4-3 comeback win over the Braves at Turner Field.
To preserve the one-run lead, Giancarlo Stanton made a diving catch in the ninth to rob Dan Uggla of a game-tying, extra-base hit.
Marcell Ozuna homered and drove in two runs.
The all-around team effort enabled the Marlins to take two of three at Turner Field. Miami has now won four straight series.
"It sure feels good," Marlins manager Mike Redmond said. "I know those guys out there are fired up. That first game they beat up on us pretty good, and we endured some rain and got some big hits and big pitches."
After rallying from three runs down in the first inning, the Marlins responded off one of the best closers in the game.
Kimbrel issued ninth-inning walks to Ed Lucas and Logan Morrison. With two outs, Solano laced an 89-mph slider into right field, scoring Lucas with the decisive run.
Solano had two strikes on him, and he was thinking fastball when he ripped an offspeed pitch into right.
"I know it is not easy coming off the bench and facing a good pitcher," Solano said. "I just focused on getting a good pitch and just hitting it. I waited for the fastball and I made the adjustment for the breaking ball."
The surging Marlins are 19-11 since May 31, and they improved to 13-15 in one-run games.
Closing out the ninth on Thursday was a challenge.
Steve Cishek picked up his 17th save, but he needed an assist from Stanton. With one out and Freddie Freeman on first, Uggla lined a ball into the gap in right-center.
Stanton is listed at 6-foot-5 in the media guide, but he says he is actually 6-5 3/4. He reached out fully and made a remarkable catch to save a run.
"I needed every bit," Stanton said. "In watching Uggla all day, I didn't think he was going to try to flick it over first base [for a base hit]. I figured he would either try to get into one or nothing. So I was conscious about the gap already. The gap is more important in that situation anyway. If he hits it into the gap, he can score."
Redmond called the play one of the greatest catches he's ever seen.
In disbelief, Uggla stood in frustration, looking in Stanton's direction.
"I was surprised he went and got it, because off the bat, it had them split perfect," Uggla said of right fielder Stanton and center fielder Ozuna. "It must have had a little bit of fade, and it just hung up there enough for him to run it down, so he made a good play."
A year ago, the Marlins were 4-14 against the Braves, including 2-7 at Turner Field. So rebounding from an 11-3 loss on Tuesday to take the series was satisfying for a team striving to come of age.
Stanton's great grab wasn't the only big defensive play on the night for Miami.
Shortstop Adeiny Hechavarria made one of the team's top gems of the season in the sixth inning, snaring Jason Heyward's liner earmarked for left field.
The series finale marked the Marlins debut for Henderson Alvarez, acquired from the Blue Jays last November. Alvarez opened the season on the disabled list with a right shoulder inflammation. He worked five innings, allowing three runs on five hits.
Atlanta starter Julio Teheran also was not involved in the decision, giving up three runs on six hits with seven strikeouts in five innings.
It was a highly contrasting first inning for the two starters, who threw almost the same exact number of pitches. Teheran got through the first on 22 pitches with 13 strikes, compared to Alvarez's 23 pitches, also with 13 strikes.
The results were dramatically different, as Teheran struck out the side in order, while Alvarez was tagged for three runs on four hits.
Andrelton Simmons led off the first by lining an infield single off Lucas' glove at third. Heyward's double put runners on second and third, Freeman ripped a two-run single and Brian McCann delivered an RBI double.
"I felt like my command wasn't there in the first inning," Alvarez said in Spanish. "After that, I was able to get into the zone."
After McCann's double, pitching coach Chuck Hernandez made a mound visit, and whatever he said worked. Alvarez retired the next two batters on two pitches, and he retired eight straight through the fourth inning.
"Chuck said to focus on spotting a good fastball on the outside part of the plate and get a ground ball," Alvarez said. "That's a first-place team, and I'm happy I was able to contribute."