The Nationals' rally fell short in the ninth because they needed to score three runs instead of just two.
Jayson Werth's second two-run shot of the game pulled the Nationals within one at 6-5.
The reason they needed three to tie was a costly run scored by the Pirates because of a wild pitch.
Looking back at the eighth inning, a wild pitch by Drew Storen allowed the Pirates Pedro Alvarez to break for home. Nationals catcher Wilson Ramos retrieved the ball and threw back to the plate, but Storen dropped the ball in the transfer to tag Alvarez out.
Pittsburgh extended its lead on that run to 6-3. The Nationals eventually lost, 6-5, when their rally fell short in the bottom of the ninth.
Manager Davey Johnson was told by Storen that the conditions caused him to have a tough time finding a good handle on the ball.
"Storen said he had trouble gripping the ball it was so hot," Johnson said. "We can't make those mistakes. We are short-handed with Zim's outing and extra innings and (Ross) Ohlendorf going Friday. We are short out there. It makes it tough."
Storen agreed with his manager. The wild pitch was costly and he knows he must figure out how to solve uncorking an errant pitch to home, especially with a runner on third.
"Yeah, you look at how many wild pitches I have had all year. It is an adjustment I need to make. Obviously, I am not happy with it."
It was only Storen's second credited wild pitch of the season. But the play at the plate turned out to be more critical to this game.
"I caught it right in the palm," Storen said. "I tried to catch it and get the tag down quick because you know he is coming in. I just didn't catch it in the pocket. As I put it down, it just slipped out."
Storen actually threw two pitches that were wild during the at-bat for the Pirates light hitting shortstop Clint Barmes. Only one allowed a runner to advance, so that was the pitch listed as a wild pitch in the final box. Ramos said those two errant pitches on fastballs were out of character for Storen.
"Never see that before with him," Ramos said. "I don't know what happened on that one."
Storen knew that the bang-bang play, a wild pitch and then a dropped ball at home plate cost the Nationals the game.
"That is the way it is at this level," Storen said. "These games, there is not a lot of margin for error. That is what happens when you make a mistake, people are going to make you pay for it. It is time for us to start making people pay for their mistakes."
Ramos agreed that it has been little mistakes that have added up to big losses for the team all season long. They must cut down on mistakes to have a chance against good ball clubs.
"The game is hitting and defense," Ramos said. "We can make a couple of runs (but) if we don't play good defense we can lose games. We have to put those two things together, defense and hitting."