Stanton hit his 12th home run in May to tie the franchise record for a single month, and the Marlins completed a three-game sweep of the first-place Washington Nationals with a 5-3 win Wednesday night.
Stanton hit a solo homer in the seventh inning, his 13th this year, and had a two-out RBI single in the first. Still only 22, Stanton tied Dan Uggla's team record for the most homers in a month and totaled 30 RBIs in May.
With the Marlins off Thursday, Stanton said he's not sorry to see the month end.
"The season's not May," he said. "Keep going."
Since the start of the expansion era in 1961, the only other player under age 23 to total more homers and RBIs in a single month was Bob Horner in 1980, the Marlins said, citing information from the Elias Sports Bureau.
"Impressive," said teammate Josh Johnson, who pitched six innings for the win. "He can do that all year long. We're excited to have him on the team."
The Marlins rallied from a 3-1 deficit and lead the majors with 20 comeback victories. They went 21-8 in May, best in the majors, and a franchise record for victories in any month.
"Things are finally coming together as they should," Stanton said. "It's games and series like these that show how good we are."
Miami is seven games above .500 for the first time and trails Washington by a half-game in the NL East. The Marlins went 7-3 during their longest homestand of the year.
"We're in a great position," manager Ozzie Guillen said. "I don't see any reason why we can't continue to play the way we're playing."
Johnson (3-3) gave up three runs before settling down and singled home the tying run with his first hit of the year. He then dirtied the front of his uniform with a headfirst slide into second base.
"My son is going to be pumped, because that's all he asks about -- hitting and sliding," Johnson said. "He'll love it."
Johnson and Anibal Sanchez are a combined 16-0 against the Nationals. Sanchez beat them Tuesday.
Edward Mujica retired all six batters he faced, and Heath Bell followed with a scoreless ninth for his third save in the series and 10th this year in 14 chances. Bell struck out pinch hitter Rick Ankiel with runners at the corners to end the game and lowered his ERA to 7.20.
Stanton's latest tape-measure homer came on a 2-2 slider off Ryan Perry. The estimated distance was 413 feet.
"You can't make a mistake on a hitter that's as big and strong as him," Nationals manager Davey Johnson said. "Perry threw him a little backup slider and, man, did he straighten it out."
Danny Espinosa had a triple and an RBI single and scored twice for the Nationals, and Roger Bernadina drove in two runs. Washington went 1 for 7 with runners in scoring position and 2 for 19 in the series in those situations while scoring only seven runs.
The Nationals finished 15-13 this month, their best May since the franchise moved to Washington in 2005. They concluded a 5-4 trip.
"It doesn't feel good to get swept," Espinosa said. "But if you look at the overall picture, we did play well on the road."
Washington's Chien-Ming Wang (1-1), making his first start of the season, allowed four runs in four-plus innings.
"I think my tempo tonight was a bit on and off," Wang said through a translator. "Sometimes I felt rushed, sometimes felt too slow. I'm kind of disappointed in myself."
Catcher Jhonatan Solano, who joined the Nationals on Tuesday, made several defensive contributions in his first major-league start. His sweep tag in the second inning nabbed Bryan Petersen trying to score from third on a flyout to right fielder Bernadina. Solano twice threw out Ramirez trying to steal second base.
RHP Henry Rodriguez was the latest player to get hurt for the injury-plagued Nationals. He slammed a finger on his right hand in a bathroom door and threw on the side Wednesday wearing a rubber protective piece. Davey Johnson said Rodriguez might be available to pitch Friday. ... Marlins 2B Omar Infante made a diving catch of Bryce Harper's liner to rob the rookie in the fifth. ... Ramirez hiked his career average against the Nationals to .380 (76 for 200). ... Uggla hit 12 homers in May 2008. ... Donovan Solano affectionately tapped the shin guard of the Nationals' catcher -- his brother -- stepping to the plate to pinch hit in the eighth. He then walked.