"Against a guy like [Dunn], it's important, lefty-lefty, to stay short," manager Matt Williams said. "All we need is a base hit. He did that, worked the count full and just stayed short on the ball and hit it into right. He's been doing it all year for us."
The knock secured the Nats' 34th comeback victory -- and 90th win overall -- of the season. The rally took off when Ian Desmond led off the seventh with a single to center off Cosart. Ryan Zimmerman, in the lineup for the first time since July 22, drove him in with a triple three pitches later. Although Zimmerman was cut down trying to score on a Wilson Ramos grounder -- which was confirmed on review -- Asdrubal Cabrera picked up the slack to tie the game at 2 with a triple of his own.
Cabrera scored on Span's hit, but the Nats stranded two other runners to end the frame. The three runs, though, were enough for the Nationals to continue their journey for home-field advantage. Drew Storen recorded his eighth straight save and starter Jordan Zimmermann earned his 13th win of the season.
"A really good win against a pitcher that's been very, very good," said Zimmerman, who went 2-for-3 in his return -- and hit a triple for the first time since May 4, 2013. "One of the best pitchers in the big leagues for the past couple of months."
But Washington's hopes weren't looking bright from the outset. Zimmermann allowed the Marlins to jump out to an early one-run lead with four hits in the first inning, one of which was an RBI single by rookie Justin Bour, who drove in both Marlins runs on Thursday.
Then a sequence of errors in the fourth inning put the Nationals down by two runs. After Zimmermann got the first two outs of the inning with just five pitches, the Marlins' Reed Johnson drilled a double to deep center field. The ball bounced off the wall, and Span, who had just made a leaping catch two batters earlier, reached up to grab the ricochet. But on the relay to the infield, the throw got away from Cabrera, forcing Zimmermann to back the play up.
Zimmermann attempted to throw Johnson out at third, but the ball went under third baseman Anthony Rendon's glove as Johnson slid in. Johnson scrambled to his feet and made it all the way home when the ball rolled up the third-base line. Both Span and Zimmermann were charged with errors on the play.
"I knew I overthrew the first cutoff guy, but I thought the ball was gonna get caught," Span said. "I turned my head and all of a sudden I heard the crowd roaring. I was like, 'What the heck is going on?' Next thing you know, he was rounding third."
As if sloppy play wasn't enough, the Nationals couldn't get much going against Cosart in the first six innings. They weren't without chances, as they had eight baserunners on and put four of them at second base. But they ended each of the first three innings on double plays.
And on the Nats' first chance to get a runner to third base, Jayson Werth was caught stealing for the first time this season to make the second out of the fourth inning. He had been successful in his previous nine stolen-base attempts.
"It could have been really ugly if I don't get some huge defensive plays behind me," Cosart said. "I made some key pitches when I had to."
Washington also had a scare in the sixth inning, as Miami's Casey McGehee cracked a line drive up the middle that glanced off Zimmermann's right shoulder. The ball deflected over to Cabrera, who got rid of it quickly for the first out. But Zimmermann laid flat on the mound for a few seconds.
Williams and team trainers came out to check on the right-hander. They watched him throw a practice pitch, and eventually Zimmermann managed to wave them off. The bullpen began to stir almost immediately. Zimmermann retired the next two batters he faced on a strikeout and a flyout. He was lifted for a pinch-hitter in the top of the seventh, in agreement with his manager that staying in the game any longer wouldn't be a smart move.
"Tonight he would've been fine, because he's warm and he's going," Williams said. "Tomorrow morning he'll wake up sore, though. We'll see how he is over the next few days."