Batting third for the first time this year, Stanton hit a three-run line drive into the home run sculpture at Marlins Park in the fourth inning against Matt Harvey (5-6). With that, the MLB home run leader ended a drought of 29 at-bats without one.
Stanton's homer total is the highest since Ryan Howard hit 58 in 2006. Stanton added a run-scoring single in Miami's seven-run fifth.
The Marlins, back home after a trip extended by three games due to Hurricane Irma, won for only the fourth time in the past 21 games.
Marcell Ozuna had four hits, including his 34th home run. Dee Gordon also had four hits, among them a two-run triple. Ichiro Suzuki added two hits and an RBI, while rookie Brian Anderson drove in two runs with his first career triple.
Stanton came into the game batting .147 in his previous 19 games. He has been rested and held out of the starting lineup three times in the past 10 games, including Sunday.
Maybe it was the latest breather, or the move one spot down in the order that helped Stanton shake his slump.
Or perhaps it was the Mets. Every Miami starter got a hit, and seven New York pitchers combined to allow 19 hits.
Dan Straily (10-9) gave up one run in five innings and struck out eight.
Harvey allowed seven runs and 12 hits in four-plus innings. He has given up 18 homers in 842/3 innings this year, and his ERA is 6.59.
The righthander has an ERA of 13.19 in four starts since returning from a right shoulder injury, while allowing 32 hits in 141/3 innings.
Mets: RHP Noah Syndergaard (lat muscle) threw 39 pitches in a simulated game and hopes to make one or two starts before the season ends, but knows he's racing the clock. "I don't want to try to rush it and jump back out there too early," he said. "It's a serious injury. I've heard a lot of stories about people reinjuring themselves. I want to make sure that doesn't happen."