In the first inning with two outs and right-hander Tanner Roark on the mound, Stanton doubled to right field before scoring on a single by Casey McGehee.
Two innings later, Miami made it a 3-0 game against Roark. Derek Dietrich was hit by a pitch with two outs. It turned out to be the turning point of the game. Roark was trying to throw a pitch inside, but hit Dietrich on the elbow.
"I just wanted to get there, not even for a strike really, and I kind of overthrew it and hit him in the elbow pad," Roark said.
Then came Stanton to the plate, and he hit a mammoth home run over the center-field fence. The ball hit the back wall behind the fence. Center fielder Denard Span knew it was gone as soon as the ball was crushed. The ball went an estimated 447 feet, according to ESPN. It was Stanton's 21st home run against Washington, and 14th home run at Nationals Park.
"He is really a good hitter. He has big power," catcher Wilson Ramos said. "We have to be careful with that guy."
Asked why he performs so well against in Washington, Stanton said, "I don't know. It happens in baseball. Some things you can't explain like that. It's just good it worked out today. But I understand I do a little better here. I can't really attest it to anything."
Manager Matt Williams declined to give a scouting report on Stanton, but said he was thrown a hanging breaking ball.
"If you hang that breaking ball over the plate, sometimes it gets whacked, and it got whacked today," Williams said.
Roark pitched seven solid innings, allowing the three runs on five hits while striking out four batters. Afterward, Roark said it was time to move on and think about Tuesday's game.
"The first couple of innings, I felt like I was aiming the ball, not throwing it the way I wanted to and not executing some pitches," he said. "I felt good. I keep plugging away. ... We'll go out there tomorrow and get a W."
Right-hander Nathan Eovaldi started for Miami and lasted 6 1/3 innings, allowing two runs on three hits. The two runs came in the sixth inning when Adam LaRoche swung at the first pitch and homered over the right-field wall to make it a one-run game.
"It's a frustrating game today," LaRoche said. "We didn't give ourselves a ton of opportunities. We didn't beat ourselves in any way. We are not on base enough. It's a frustrating loss."
Outside of the LaRoche home run, the Nationals collected just two hits. The team is batting .223 in May. It doesn't help that the Nats are missing some big bats in the lineup. Bryce Harper and Ryan Zimmerman haven't played since April because of thumb injuries. The pitching has been above-average, but the defense is ranked the worst in the National League.
"We are not hitting very well right now," Ramos said. "We have a pretty good team, good hitters, but we need to work on that. We need some runs. If we want to win, we have to score some runs."
Said LaRoche, "When one guy struggles, it tends to be contagious at times -- whether it's pressing and trying too hard or just running into some good pitchers. I have a feeling it's a little bit of both right now. Not putting the big inning together today, we should have done better than that."
Once Eovaldi left the game, relievers Mike Dunn, A.J. Ramos and Steve Cishek blanked the Nationals the rest of the way.