That proved to be the difference in the sixth inning with Hanley Ramirez on second base -- after a walk and his second steal of the game -- and nobody out.
At that point, John Baker hit a hard comebacker to Martis, who fielded it, turned around and had Ramirez hung up between second and third. Martis fired to second base right away -- instead of running at Ramirez first -- and Cristian Guzman's snap throw to third went wide of Ryan Zimmerman, allowing the Marlins shortstop to score, giving the Nationals a one-run deficit they wouldn't cut into.
"It's part of the learning process," manager Manny Acta said. "The kid should've never thrown the ball. He should run to Hanley, make him commit either way, and then make the throw. For the most part, you always try to throw to the third-base side, so that if Hanley comes back, he's going to be safe on the preceding base.
"But, he's 21. He's here to learn those things."
Before that fateful sixth inning, Martis was pretty much unhittable. With his consistent low-90s fastball working and his dazzling changeup keeping hitters honest, the rookie right-hander gave up just one run on two hits, while striking out nine in the first five innings. In those five frames, Martis -- who allowed just two runs in five innings in his debut on Sept. 4 -- struck out five straight batters at one point and only allowed one runner to get into scoring position.
"If I keep pitching like this, I'm going to keep getting better and better and better," Martis said.
His catcher, Wil Nieves, felt the same way.
"He was throwing his fastball downhill, and his changeup was unbelievable," said Nieves, who was catching Martis for the first time. "He kept the hitters off balance, and he was hitting the corners.
"This is my 13th year [as a pro], so I have caught a lot of guys and he was pretty impressive."
The Nationals took a 1-0 lead in the top of the second with a RBI double by Anderson Hernandez. With runners on first and second and two outs, Hernandez -- who went into the at-bat four for his last 19 -- smoked one to the left-center-field gap off Florida starter Scott Olsen to get Washington on the board.
But after averaging over eight runs per game in their last four contests, the bats went silent thereafter on Friday.
"Every day is a new day," Acta said. "I would love to sit here and say we should've borrowed a couple of runs from [the series against the Mets], but it just doesn't happen that way."
On Friday, Washington left 11 runners on base and hit 1-for-6 with runners in scoring position.
After Hernandez's RBI double in the second, the Nationals loaded the bases later that inning, but were unable to add to their lead, after Zimmerman flied out to end the frame. In the eighth, Washington had runners on first and third with two outs, but Marlins reliever Joe Nelson got pinch-hitter Kory Casto to pop out in foul territory to end another threat.
The Nationals also had a couple of balls that just missed going out.
With one out in the ninth inning, Guzman hit a shot off Matt Lindstrom that landed just a couple of feet in front of the wall in right field and Lastings Milledge did the very same thing with two outs in the seventh.
"It's baseball; you can't score runs every day," said Zimmerman, who went 1-for-4 with a walk and a strikeout. "We had chances and we just couldn't get the runs in."
The Marlins tied the score in the bottom of the fourth with a leadoff home run to deep left by Jorge Cantu. With Cantu's 25th home run, the Marlins became the first team in Major League history with four infielders to post at least 25 dingers in a season.