"Yeah, that's what you've got to do. You've got to keep trying to win ballgames. I'm glad we've got four in a row and hopefully (we) keep going," manager Fredi Gonzalez said.
Pinch-hitter Brett Hayes also homered for the Marlins and Johnson (14-4) allowed two hits over five innings. The right-hander walked three, struck out one and retired his final 11 batters in Florida's fourth straight victory. He is 7-2 in his last 10 starts, and 5-0 in his career against the Nationals.
"I finally found a groove and was throwing my slider for strikes. It was a good slider," Johnson said. "Some little things mechanically were a little bit off in the first two innings, but after that it was good."