Nationals right-hander Dan Haren struggled from the start Friday night, allowing the first four batters to reach base. Rookie Jose Fernandez allowed just one hit in seven innings for the Marlins.
The result was a 7-0 Miami win at a time of year when the Nationals are desperate for wins in every game they play.
Manager Davey Johnson was impressed by the Marlins' young rookie starter.
"He really used all his pitches," Johnson said on MASN's "Nats Xtra." "He was really attacking our hitters, going after everybody, throwing strikes. That is the key. He had good location, good fastball, good breaking stuff. Maybe once or twice, he got behind in the count. He was really very aggressive. Had a good changeup to go with his good fastball and breaking stuff."
Johnson said the six hits early on got Haren in a big hole.
"Haren had his problems," Johnson said. "I was a little worried about it. I took him out after three. I was worried about his hand. I wanted to get some guys in my pen some work."
Haren got hit on his ring finger trying to field a comebacker. Johnson said there was "no sense" in continuing with Haren after that.
Despite using five relievers, Johnson said all of his relievers would be available Saturday night.
The Reds held off the Dodgers 3-2 to take an eight-game lead over the Nats for the final wild card spot. There are only 22 games left on the regular season schedule.
"We got to win," Johnson said. "We just need to win ball games. We can't afford to be losing. Period."
Johnson said Denard Span (groin tightness) is "iffy" for Saturday's game.