"That was a great comeback against a great pitcher," said manager Bobby Cox, whose Braves had lost four of their previous five games and six of eight. "It's good to get it turned around. We've just been on this little losing streak, and we needed to snap it."
Jason Heyward, Martin Prado and Derrek Lee had run-scoring hits in the sixth, and Brian McCann's sacrifice fly to the wall was dropped by right fielder Jon Jay for a two-run play that put the Braves ahead 6-4.
That spiked the decibels to a level that hadn't been heard recently at Turner Field, as the Braves' previously stellar home performances had begun to wane.
The Braves had lost six of their past eight games overall, including two in a row at home. They got the vibe back Friday night, for one inning when they needed it badly.
"We got off to a good start that inning, and to put up all those runs was big for us," Conrad said. "And to have the pitching to hold them off.
"We've got to be playing better baseball, and I thought we did that tonight. It was definitely a big win for us, but every game from here on out is going to be a big one. We've just got to get back to playing better baseball like we did tonight."
Despite a second-inning homer from Nate McLouth, the Braves trailed 4-2 after five innings.
"It's so hard to come back against [Carpenter], said McLouth, who contributed sacrifice in the pivotal sixth. "You can't think five and six runs at a time, you have to try to chip away. We had a bigger inning in the sixth inning than a lot of people probably expected to happen."
Braves rookie left-hander Mike Minor left without recording an out in the sixth inning. He was charged with four runs and seven hits in his sixth major league start, including Matt Holliday's two-run, two-out homer in the third inning and Carpenter's two-out homer in the fourth.
It was the second career homer for Carpenter, who also had a two-out RBI single in the second, doubling his season RBI total with two Friday.
"He made mistakes tonight," Cox said of Minor, "but he threw OK. Nothing great tonight."
In Thursday's series opener, the Braves fell behind 5-2 in the second inning against Adam Wainwright and didn't put up much of a fight the rest of the way. On Friday, they fell behind again, but stormed back against Cardinals co-ace Carpenter.
The Braves trailed 4-2 before four consecutive hits to start the sixth -- singles by Conrad, Omar Infante and Heyward, and a game-tying double to left field by Prado, who stood at second, shouted excitedly and pumped his fists.
"The last two weeks, I wasn't feeling right in the batter's box," said Prado, who hasn't felt completely comfortable since returning from a broken pinkie. "Tonight I got excited because, for me, I felt like I hit a ball hard for the first time in a long time, and that was a good time to let my teammates know that I'm doing the best I can.
"Even if I'm not doing well, I come to the field and do my best. If I don't do well, I want to just let them know I'm here and doing everything I can do win game."
Next up was McCann, whose towering fly was dropped by Jay just before the right fielder ran into the wall. Two runs scored on the play, then Lee singled to drive in the fifth run of the inning. That was all for Carpenter.
The Cy Young Award candidate faced six batters without recording an out in the sixth, allowing five hits in the inning and eight in the game. Carpenter was charged with eight runs (six earned) in his worst start of the season.
He had a 2.28 ERA in his past 11 starts before Friday and allowed three earned runs or fewer in all of those games.
"We knew it was going to be hard against Carpenter and the Cardinals," Prado said. "They've got a great pitching staff. But we've got to believe in our guys.
"We came today with a mission, to get good at-bats, work the count and do anything that we can to change things offensively. That's one of the main reasons T.P. [hitting coach Terry Pendleton] was telling us, ‘We're going to watch videos and do anything we can do to make adjustments.' That's what we did today."
The six-run sixth marked the first time the Braves scored more than five runs in an inning since a seven-run fifth against the New York Mets on Aug. 31, in a 9-2 win at Turner Field.
Pendleton had to watch Friday's scoring burst on a clubhouse television after being ejected during the Cardinals' third inning for arguing a checked-swing call from the bench.
Braves reliever Peter Moylan (6-2) struck out the last two batters with a runner on base in the sixth inning for the win, and Billy Wagner recorded his 33rd save.
Minor has a 7.71 ERA in his past three starts and has lasted five innings or fewer in each. He worked six innings or more in each of his first three starts.
He's allowed 16 hits (three homers) and 10 earned runs in nine innings over his past two games, and the young lefty conceded that he's tiring a bit late in his first full season of pro ball.
"I did the best I could with what I have right now," he said. "The fastball's kind of – the velo [velocity] is down right now and I'm not really hitting spots. The curveball I thought was a little better this week, but I still didn't get any swings on it, and when I did it was the home run [by Holliday]....
"Right now I'm just kind of getting worn out. But at the same time, I'm still good for the rest of the season. I don't need to be shut down or anything like that. But it's a little harder for me, whenever I try to gas up, I look back and it's 92 or 91 [mph]. Early in the year I was hitting 93, 94."