The Braves were clear that this road trip - St. Louis, New York and Milwaukee - was their toughest yet. It couldn’t be off to a better start.

Propelled by a five-run sixth, the Braves held on to beat the Cardinals for the third straight game, 6-5, on Sunday. It marked their first sweep in St. Louis since 2012.

The Braves already have more wins on this trip (three) than they had in the past homestand against lowly Baltimore and Cincinnati (two).

“It was a well-played series,” manager Brian Snitker said. “We came off a tough homestand and came here at the beginning of a rough road trip. So it’s good to get out of here with three.”

Despite Sunday’s one-run affair, the series wasn’t particularly close. The Braves outscored the Cardinals 22-10. Their starters produced a 0.00 ERA, whereas St. Louis’ was responsible for a 7.16 posting.

The Braves hit .287 with a .367 average with runners in scoring position. The Cardinals hit .206 with just a .200 mark with runners at second and/or third.

“It’s a good team, man,” Cardinals first baseman Jose Martinez said before Saturday’s game. “It’s a good team. They run, they hit, good at-bats. They have a lot of experience on the team. They know how to play baseball.

“When you play smart baseball, good things are going to happen in the games. They took advantage of a lot of situations. … They don’t strike out much. Overall, that’s a good balanced team.”

Mike Foltynewicz grinded through the uncomfortably hot and humid temperatures, providing five shutout innings with nine strikeouts in the finale. Marcell Ozuna’s fourth-inning single was the Cardinals’ only hit against Foltynewicz.

“I would’ve liked to go a little deeper, but that heat was a killer,” Foltynewicz said. “They had to deal with it too. It’s tough for me to eat before games, and if you don’t get food in you, it definitely takes a toll on you. I just feel like my stomach shrunk up a little bit. My arm felt amazing, actually.”

Foltynewicz’s 2.02 ERA is second-best in the National League, trailing only Mets ace Jacob deGrom (1.84). He’s allowed no more than two runs in 15 of his 16 starts.

St. Louis made a late run with a five-run inning of their own in the seventh. With two on, Francisco Pena knocked in the Cardinals’ first two runs, chasing Shane Carle from the game.

Jesse Biddle induced a grounder then walked Matt Carpenter. Biddle, who’s held right-handers to a .092 average, was lifted so veteran Peter Moylan could face the right-handed Tommy Pham.

Pham hit a three-run homer, pulling the Cardinals to within a run. The outfielder was riding an 0-for-31 streak before collecting two hits later in the game.

“It was playing match-ups right there,” Snitker said. “Biddle’s good against right-handed hitters. At that point in time, I’m not going to second guess myself. That’s what we’ve got Peter down there for, to go after the right-handers. If I had to do it over, I’d do it again.”

Charlie Culberson, as he has been all year, aptly filled in at third base for Johan Camargo on a rest day. Culberson put the Braves on the board with an RBI-double in the second, and later singled home the team’s fourth run.

First baseman Freddie Freeman, who entered the day hitting .170 in his last 11 games, snapped his slump with a towering two-run shot to right.

“It’s coming,” Snitker said. “Somebody’s going to pay. It’s just one of those things that everybody goes through. He’s working and we still have unbelievable confidence in him and what he brings. You feel like he’s going to do something special every time he goes up there.”

Cardinals starter John Gant went 5-1/3 innings, allowing four runs, in his first start against the Braves. Gant made 20 appearances (seven starts) for the Braves in 2016.

The Braves travel to New York and open a three-game series with the Yankees on Monday before finishing with four in Milwaukee.