Harang (3-2) gave up 10 hits in 4 2-3 innings, and his ERA rose from 0.85 to 2.97. The Marlins tied a season high with 15 hits, including seven for extra bases.
Miami's 9-0 lead after five innings was a rare luxury for Eovaldi (2-1), who has the lowest career run support among active major-league starters. The right-hander allowed three hits and one run to lower his ERA to 2.58.
Casey McGehee had three hits and Adeiny Hechavarria legged out a double and a triple for the last-place Marlins, who have outscored the NL East leaders 18-3 in the first two games of their series. The Marlins will sweep a series from Atlanta for the first time since 2009 if they can beat Ervin Santana on Thursday.
The Marlins are batting .307 in their spacious ballpark, where they're 11-4 to lead the majors in home victories. They're batting .215 on the road, where they're 2-10.
The Braves totalled six hits, including Justin Upton's eighth homer.
Harang had allowed a total of three runs in his first five starts, but the Marlins scored four against him with four consecutive hits to start the second inning. Garrett Jones singled home the first run, and Ozuna followed with his fourth homer.
Hechavarria tripled and Yelich hit a two-run homer in the fourth to make it 7-0.
The nine runs allowed by Harang matched his career high. He fell to 5-5 in 15 starts against the Marlins with an ERA of 6.54.
Eovaldi allowed a double by Jason Heyward to start the game, then held the Braves hitless until the sixth.
Notes: Braves RHP Gavin Floyd is ready to come off the disabled list after recovering from elbow surgery a year ago, but manager Fredi Gonzalez was noncommittal regarding how he will be used. Floyd isn't scheduled to start this week. ... Marlins INF Rafael Furcal (hamstring) took grounders before the game is scheduled to resume his rehabilitation assignment this weekend with Triple-A New Orleans. ... Miami RHP Jose Fernandez estimated that in his victory Tuesday he threw 30 changeups, twice his previous high. ... Santana (3-0, 1.95 ERA) starts Thursday for the Braves against Miami's Henderson Alvarez (1-2, 2.73).