Adam LaRoche went 2-for-3 with a two-run single, and he torched the Marlins all series. In the four games, the Nationals first baseman was 7-for-15 with three home runs and seven RBIs.
Ricky Nolasco was tagged for four runs, all in the second inning, and he pitched six innings, dropping his fifth straight decision.
"Ricky threw the ball better today than he was the last couple of outings," Marlins manager Ozzie Guillen said. "Very tough second inning. He left some balls over the middle of the plate. I thought he was going to be worse, knowing it was hot and humid."
There was action in Miami's bullpen in the second, but Nolasco was able to settle after the inning and made it through six.
"They had me on the ropes there early," said Nolasco, now 8-11 on the year. "I was just trying to survive and hang on and give my team a chance."
In an otherwise lackluster game, Jose Reyes and Carlos Lee extended their respective hitting streaks. Reyes now possesses the longest hitting streak in the Majors this season, reaching 24 games, surpassing the 23 previously set by Robinson Cano of the Yankees from June 24 to July 20.
"Carlos is a professional hitter," Guillen said. "He's an RBI man. Jose, there are not that many players in the game like Jose. He gives you everything he has every day. And he gives you good at-bats every day."
Already his personal high, Reyes is now one game shy of matching Kevin Millar for third place in franchise history. Millar hit safely in 25 in a row in 2002. The club mark is 35, set by Luis Castillo in 2002. And Emilio Bonifacio is second with a string of 26, turned in a year ago.
Reyes' streak started on July 13, Miami's first game after the All-Star break, and it was kept alive in the fourth inning.
Reyes isn't the only Marlin riding a hitting streak. Lee doubled to lead off the seventh inning, improving his string to 11 straight games. Lee collected his double in the seventh inning off Craig Stammen. Greg Dobbs followed with a double, resulting in Miami's only run.
Strasburg was never seriously threatened on his way to improving to 12-3 on the season.
The Nationals right-hander also extended his string of scoreless innings against the Marlins to 27 innings, including 18 this year.
"You do not [often] see a legit No. 1 guy," Guillen said. "Like this is a No. 1 guy. When Justin Verlander started, he struggled in the beginning of his career, and he started getting better. CC [Sabathia], the same way. But this kid, from the first day he got into the big leagues, he got a lot of people's attention. He handled it very well."
Asked to compare Strasburg to a pitcher from Guillen's playing days, the Miami manager replied: Roger Clemens.
"I don't see him every day," Guillen said. "But the last couple of starts, he's not 99 [mph], 97, trying to strike out people, and trying to give you the best breaking ball he has.
"I think he's maturing, knowing how to pitch now, and he's better. With that stuff, he don't need 99, 98. He spots the ball very well. He seemed like he was tired at the end. But it was 100 degrees out there, he should be tired. I think right now, he's improved a lot."
Strasburg was removed after throwing 91 pitches, with 55 for strikes.
"I feel like I need to prove something every single day," the All-Star right-hander said. "There's not a single game that I take lightly or feel like I don't need to go out there and perform. I want to do it every time out."
While Reyes has been able to prolong an individual mark, the Nationals were able to string together some key hits to secure a four-run lead in the second inning.
The big inning carried the Nationals throughout the series. They rallied to a 10-7 win on Saturday, scoring six runs in the eighth inning.
It was the second inning on Sunday that swung momentum. Washington sent nine to the plate, scoring four times off Nolasco. Jayson Werth got the inning rolling with a single to left, and Nolasco plunked Danny Espinosa with an offspeed pitch. With one out, Strasburg slapped a two-run single to right field.
Strasburg has driven in seven runs this year, with three against Miami. LaRoche punctuated the inning with a two-out, two-run single to provide a four-run cushion.
"Once again, a pitch here or there kind of ruins the game for me and the team," Nolasco said. "That's what good teams do, they don't miss those pitches when you miss.
"Adam LaRoche is the hottest guy in the league right now. He does a good job. Leave that pitch up to the pitcher, and he does a good job. ... You'd like to have a pitch back here and there, but you can't. You just have to keep battling and keep going out there and be out there as long as I could."