Mike Stanton hit a pinch-hit RBI single in the 4 win over the Braves in the game series.
Florida escaped several extra-inning threats by Atlanta to come away with its fourth straight win.
John Buck walked on five pitches to lead off the 12th and pinch runner Brett Hayes went to second base on Bryan Petersen's sacrifice bunt. Anthony Varvaro (0-2) intentionally walked Donnie Murphy and was replaced on the mound by Cristhian Martinez, who surrendered Stanton's go-ahead single to left.
Stanton missed the previous two games with a strained right hamstring and got ready to hit a few times before the Marlins finally called on him. He said nothing changes in his approach when he's pinch hitting.
"I just take it as I'm getting ready for a game," he said. "If we're on the road, I'm going to bat in the first inning anyway. So it's kind of like my first inning, but usually in a more important situation."
Leo Nunez pitched around a leadoff walk to Jason Howard in the bottom of the 12th, picking up his 35th save. He sealed the win for Clay Hensley (4-6), who pitched out of trouble in the previous two innings.
The Braves, who had tied the game on Alex Gonzalez's RBI single in the eighth inning, lost their fourth straight game but remained 4 1/2 games up for the wild card lead after St. Louis also lost Monday.
"We're fine. We played good today, we just didn't come out with the win," said Braves reliever Jonny Venters, who pitched the eighth. "We've gotta just keep going and every day is a new day. We've gotta come to the field tomorrow to try to get a win."
With two outs in the eighth, Jason Heyward singled, went to second on Murphy's errant throw from short and scored on Gonzalez's line drive into left field to make it 4-4.
Hayward drew a leadoff walk in the 10th and advanced all the way to third, but was stranded there when Murphy gunned Bourne down on a bang-bang play at first base to end the inning.
Atlanta threatened again in the 11th -- and it took a backhand stab by Murphy to save the Marlins.
With two outs and runners on first and second, Murphy nabbed Prado's hot shot and spun around to get the force at second base. Jose Costanza, pinch running for Chipper Jones, probably would have scored from second base if the ball reached the outfield.
The Marlins, coming off a three-game sweep of the Pirates, improved to 4-0 on an 11-game road trip. They are 4-9 against the Braves this season.
In the second, Prado raced to the warning track in left field for an over-the- shoulder catch on Florida starter Chris Volstad's long drive to end the inning.
But the Marlins pushed their lead to 2-0 in the third after Emilio Bonifacio tripled and came home on Infante's sacrifice fly.
The Braves tied the game in two at-bats. Dan Uggla and McCann led off the fourth with back-to-back singles and Uggla scored on Gonzalez's two-out double. In the fifth, Bourn and Jones hit consecutive singles to start the inning and Bourn scored on Freddie Freeman's sac fly.
Florida came back with two runs in the sixth inning to knock starter Brandon Beachy out of the game. Petersen walked and scored after Murphy and Matt Dominguez hit consecutive singles, chasing Beachy for Arodys Vizcaino.
John Baker hit for Volstad, and Murphy scored on Vizcaino's wild pitch for a 4-2 lead.
Another triple, this one by Atlanta, produced a run in the sixth when Prado reached third against Burke Badenhop and scored on Gonzalez's single.
Beachy gave up four runs on nine hits in 5 1/3 innings for the Braves, striking out 10 to raise his Atlanta rookie record to 152. Volstad allowed two runs on seven hits in five frames and remained winless in his last eight starts.
Atlanta fell to 14-11 in extra inning games this season, while Florida improved to 8-12...The Braves were swept by the Cardinals over the weekend to end a 2-6 road trip...Volstad is 0-4 since July 10.