MIAMI -- A comfortable win before a small, subdued crowd is as much excitement as the Atlanta Braves want in the final days of the race for a playoff berth.
Atlanta began the night leading St. Louis by 2½ games in the NL wild-card race after blowing a ninth-inning lead to lose Monday. The margin was 10½ games on Aug. 25.
"It was an important victory for the team," said Delgado (1-1). "There was a little pressure, but after a couple of innings I forgot about that."
The 21-year-old right-hander, making his sixth career start, pitched around five hits and lowered his ERA to 2.70.
"What impresses you about him is he expects to go out there and do that," catcher Brian McCann said. "He's not intimidated. To have that mindset at a young age is very, very impressive."
The announced attendance was 21,733, and with the turnout perhaps half that total, the home team gave fans little to cheer about. Cristhian Martinez and Anthony Varvaro both retired six consecutive batters to complete the 16th shutout for Atlanta, which ties for third-most in the majors.
The Braves won for only the seventh time in their past 19 games.
"Tonight was a big game," McCann said. "There are always teams fighting for that playoff spot; that's why this time of year is the best time in sports. We sit at the top of the wild card. We've just got to continue to win games."
Braves right fielder Jason Heyward had eight putouts, including several on running grabs.
"Heyward changed the game out there defensively," manager Fredi Gonzalez said. "He made some great catches."
The Marlins went 0 for 3 with runners in scoring position, leaving them 0 for 11 in the series in those situations. Florida fell to 1-7 at home against Atlanta this year.
"They don't give us too much to hit," Marlins manager Jack McKeon said. "What they give us to hit, we can't do much with."
Anibal Sanchez (8-9) lost to the Braves for the third time this season in as many starts. He allowed three runs in five innings but retired the last 11 batters he faced.
It looked as though the Braves' recent slump might continue when they put runners at second and third with no outs in the first and failed to score.
But they bounced back with three runs in the second. Alex Gonzalez hit the first pitch for a homer, and Heyward doubled. Bourn hit a one-out double and scored on Prado's single.
Freeman homered off Brian Sanches in the sixth to make it 4-0.
The Marlins loaded the bases with one out in the third, but shortstop Gonzalez turned a soft liner by Logan Morrison into an unassisted double play. There were no Florida threats in the late innings, with Braves pitchers retiring the final 13 batters.
"I'm proud of the guys for the way they bounced back tonight," third baseman Chipper Jones said. "I still would have liked to have seen us score seven or eight and make it a laugher, but we'll take it."
The Braves sent minor-league RHP Eliecer Cardenas to the Pittsburgh Pirates to complete the Aug. 31 trade for OF Matt Diaz. ... Marlins RHP Javier Vazquez, who is scheduled to face Atlanta on Wednesday, is 7-10 in 20 starts against his former team. But he hasn't faced the Braves since 2005. ... RHP Derek Lowe, scheduled to start against the Marlins on Wednesday, is 1-0 with a 1.42 ERA against them this season, with the win on Aug. 8. ... Sanchez is winless in his past eight home starts. ... Prado improved his lifetime average against Sanchez to .444 (12 for 27).