ATLANTA — Josh Johnson didn't feel he could afford to give up any runs if he wanted to beat the Atlanta Braves.
That plan was in trouble after Johnson had faced only two batters.
Johnson gave up Martin Prado's homer with one out in the first, and the Marlins' struggles continued as they were shut out by Paul Maholm and three relievers in a 3-0 loss Wednesday night.
Miami has lost six straight and eight of nine.
The Braves have won four straight, including the first two games of the three-game series.
"They're playing good baseball," Johnson said of the Braves. "You've got to throw up a zero."
Johnson (8-14) allowed three runs, two earned, four hits and five walks in six innings.
Marlins manager Ozzie Guillen said Johnson "threw the ball well" but said "The other guy threw the ball better than him.
"I don't want to take anything away from the lefty (Maholm)," Guillen said. "He shut us down."
Maholm (13-10) earned only his second win in his last seven starts. He gave up five hits with no walks and six strikeouts in 6 2-3 innings.
"I tried to do as much as I could to try to treat it like a playoff game," Maholm said.
"Obviously, this is what you play for. You want to play in October. You want to play in the postseason. It's fun to come to the park and know there's some added pressure to come in and try to do some things."
From the first inning, when Prado homered, to the ninth, when closer Craig Kimbrel struck out four, the Braves showed they haven't given up on catching Washington in the NL East.
The win came one night after Atlanta clinched at least an NL wild-card berth with Tuesday night's 4-3 win over the Marlins. After the game, Braves players sprayed champagne on each other in the clubhouse and on the field.
The Braves remained four games behind first-place Washington in the NL East. The Nationals beat the Phillies, 8-4.
With only seven games remaining in the regular season, the Braves are running out of time to catch the Nationals. They haven't given up on the chase.
"It's going to be a difficult task, but it can be done," Gonzalez said. "We just have to win and see what happens."
Prado said a strong finish to the regular season is important to the postseason hopes.
"I think the way we're playing right now, we just want to keep going all the way to the end," Prado said.
"We want to finish strong, to win as many games as we can."
Prado drove in Jose Constanza with a third-inning single off Johnson. Prado had two of the Braves' four hits.
Chad Durbin recorded the final out in the seventh. Eric O'Flaherty pitched the eighth.
Kimbrel earned his 40th save, matching Jason Motte for the NL lead, with a perfect ninth inning. He struck out four in the inning. Donovan Solano struck out but reached on a wild pitch. Kimbrel also struck out Greg Dobbs, John Buck and Gil Velazquez.
"This kid's amazing!" Guillen said of Kimbrel. "Every time he's on the mound, I guarantee you everybody in the Atlanta organization feels pretty good about it. He's one of the best ones on the mound right now, if not the best."
Kimbrel is the first Brave to record four strikeouts in an inning since Mark Wohlers against the Cubs on June 7, 1995.
The Braves scored an unearned run off Johnson in the sixth. Dan Uggla reached on third baseman Velazquez's low throw to first base for an error. Uggla moved to third on Brian McCann's single.
With Maholm at the plate, Uggla took off from third on an apparent attempted suicide squeeze. Maholm waved his bat at the pitch, which was wide of the plate and beyond the reach of Buck, the catcher. Uggla scored easily and was credited with a stolen base.
Velazquez had two of Miami's six hits.
NOTES: Uggla's steal of home was the Braves' first since Jason Heyward on July 28, 2010, at Washington. ... Braves CF Michael Bourn (jammed left thumb) missed his third straight start. ... Heyward stole second, his 20th, after a first-inning walk. ... Guillen said OF Giancarlo Stanton (sore left ribcage) may be held out until Friday's opening game of a home series against the Phillies. ... Guillen said he had no problem with the Braves celebrating after clinching at least a wild-card spot Tuesday night. "Everybody should celebrate everything they do in life," Guillen said. ... Braves RHP Tommy Hanson (12-9) will face Miami RHP Jacob Turner (1-3) in Thursday night's final game of the three-game series.