A night after Jose Fernandez and the Marlins combined for a two-hit shutout, a more energized Nationals squad took out their aggression on Eovaldi, who was tagged for five runs on nine hits in three innings.
"Eovaldi was up in the zone and they squared him up pretty good," Marlins manager Mike Redmond said. "It wasn't his night. That's kind of tough after a nice win last night. It would have been nice to go out there and get another nice pitching performance. It just wasn't in the cards. We got out of the game early, getting down 5-0. We couldn't really muster anything until the seventh."
Zimmerman's 12th multi-home run game of his career provided immediate support for right-hander Tanner Roark, who threw six scoreless innings.
For his career, Zimmerman now has 21 homers off the Marlins, his most against any team.
"They've got some guys in there who can do some damage, especially if you don't get the ball down in the zone," Redmond said. "They've got guys who can put it in the seats. You've got to execute. You've got to get ahead, and make pitches. Tonight, we just weren't able to do that."
The Marlins trailed by seven entering the seventh before they scored two runs off Ross Ohlendorf. Adeiny Hechavarria and Jeff Mathis each had RBI singles.
With the game out of reach in the eighth inning, Giancarlo Stanton was replaced due to a sore right foot.
Last Sunday at Atlanta, Stanton rolled his ankle while stepping on first base. He played through some discomfort for a week, but he said he experienced more pain about the second inning.
An X-ray taken after Saturday's game came back negative. The slugger is listed as day to day, but chances are he will not be available for Sunday's series finale.
"Today, it hurt, I don't know why, more than almost the first day that it happened," Stanton said. "I'm just calling it a bad day right now."
Coming off eight shutout innings against Atlanta, Eovaldi matched his shortest outing of the season.
"I just wasn't locating really any of my pitches," Eovaldi said. "My fastball command was off, and I really wasn't throwing any of my breaking pitches for strikes.
"In Atlanta, I was locating my fastball to both sides of the plate. Today, I was struggling to locate it to one side. When I needed to make my pitches, I wasn't. I was leaving them right down the middle, and they were putting good swings on them."
The hard-throwing right-hander last worked just three innings on Aug. 16 at home, when he gave up 11 runs (nine earned) on 12 hits.
"No. 1, [Eovaldi's] command isn't as good on all his breaking stuff," Nationals manager Davey Johnson said. "Fernandez's breaking stuff separates him a great deal, because he can throw his breaking stuff over at any time and attacks the hitters. Eovaldi is still learning to get his pitches over and command them. He's got a good arm and sometimes that comes a little later."
The Nationals came out aggressively against Eovaldi, grabbing a two-run lead two batters into the game.
Denard Span led off with a single, extending his career-best hitting streak to 18 games. After falling behind 1-2 in the count, Zimmerman blasted a drive to deep center. The ball bounced off the top of the wall, deflected upwards off the base of the stadium's home run sculpture, and made its way back onto the field.
Since the umpires didn't have a clear view, they didn't know the ball had actually left the ballpark. Initially ruling the ball was still in play, Zimmerman settled into second with a double. He signaled for a home run, and Johnson asked for a review.
The umpires, directed by crew chief Gary Cederstrom, exited the field to check the instant replay. Minutes later, they returned and overturned the double, giving Zimmerman a two-run homer.
"It looked like it was a home run," Redmond said. "To me, it looked like it hit the back wall. That's a long way. They checked it and got it right."
Two innings later, Zimmerman connected again, but this time it was a no-doubter. Zimmerman led off the third inning with an opposite-field homer, triggering a three-run inning.
Wilson Ramos added a two-run single in the inning, breaking open a five-run lead before the Marlins had a baserunner.
Roark was perfect through three innings before Chris Coghlan opened the fourth with a single to center.
"We had a couple of chances," Redmond said. "It looked like [Roark] was moving the ball around a little bit. It looked like he had a little late life to his fastball, and he kept us off balanced. He was pitching with a five-run lead, basically. That always helps."