The Post Sports Live crew debates whether Bryce Harper's comments about manager Matt Williams' lineup are potentially damaging for a team that just got back to full strength on Monday night. (Post Sports Live/The Washington Post)

An afternoon of mistakes on the base paths and at the plate by the Washington Nationals didn’t deter Denard Span. He saw a chance for an extra base and took it.

“I just trusted my instincts and just went for it,” Span said. “A little risky.”

Span’s double in the eighth inning turned into the winning run when Ryan Zimmerman drove him home four batters later as the Nationals defeated the Cubs, 2-1. Washington moved within a half-game of the Atlanta Braves in the National League East standings and a season-high nine games over .500. It received six strong innings from starter Jordan Zimmermann and overcame a rare uneven outing from reliever Drew Storen. The Nationals’ play Sunday wasn’t clean or sound, as evidenced by their eighth-inning rally, but they found a way to sneak past the Cubs.

Span led off the eighth with a line drive that died in the right field grass, and he decided to test Nate Schierholtz. Span aggressively took second base, sliding safely under the tag. A better throw would have gotten Span.

“A double right there obviously takes the inning in a completely different direction than just a single,” Zimmerman said.

But on the ensuing flyout, a ball lifted to right field by Anthony Rendon, Span didn’t tag up and try for third base. “We didn’t execute very well [Sunday],” Nationals Manager Matt Williams said.

After Jayson Werth struck out, the Cubs opted to walk Adam LaRoche intentionally and have right-handed reliever Pedro Strop face Zimmerman.

Zimmerman lined an 82-mph slider to left for the RBI single. Span raced around the bases, slid home and smacked his hands together in excitement. LaRoche, however, kept going for third, hoping a rundown between the bases would give Span enough time to score. But Span had plenty of time. Had LaRoche stayed, perhaps closer Rafael Soriano would have had a bigger cushion in the ninth inning as he notched his 21st save.

“I don’t know if they’ve got a serious chance to throw [Span] out,” Williams said. “But it’s aggressive baseball. We want to make sure we score that run. We feel good about Sori. All those things going into it there. So against a guy like that, we have to make sure we execute.”

Before the Nationals escaped with a victory, Zimmermann and Cubs starter Jake Arrieta matched each other for most of six innings. Zimmermann, who was told just before the game he had made his second straight all-star team, gave the Nationals six scoreless innings. But it was a struggle because of the inconsistent control of his fastball. He gave up at least one hit in each of his six innings.

“After the third inning I was trying to tell myself to at least make it to five,” he said.

By the end of the fourth inning, his pitch count sat at 77.

Zimmermann managed to produce quicker innings late in his start, and he left the game after six strong frames. He lowered his ERA over his past seven starts to 1.26, and he has struck out 46 batters and walked only seven in that span of 50 innings.

“The way Jordan pitched, that was a game we needed to win,” Zimmerman said.

The Nationals had a chance to give Zimmermann a bigger cushion, but the opportunity fizzled quickly. With the Nationals leading 1-0, Ian Desmond and Wilson Ramos singled to start the fifth inning. With two on and no outs, Zimmermann came up to bat. He had already completed five scoreless innings, and his pitch count was uncharacteristically high at 93.

Williams asked Zimmermann to lay down a sacrifice bunt toward third base, but the pitcher couldn’t, failing three straight times and striking out on a foul bunt. “Just botched them,” Zimmermann said. Span or Rendon could have redeemed Zimmermann, but after a flyout and a groundout, the Nationals got nothing.

A missed chance to add more runs haunted the Nationals when Storen endured a minor blip in his dominant season. Pitching for the first time in six days, Storen took over with a 1-0 lead in the seventh inning. He gave up a leadoff single to Chris Coghlan, who moved to second on a sacrifice bunt. Storen then walked Justin Ruggiano on six pitches, the biggest sin of the inning.

The Cubs delayed tying the score with a curious decision by their third base coach. After Anthony Rizzo singled to right-center, Gary Jones held Coghlan at third. As he rounded first base, Rizzo reacted in disbelief. Span made a nice running play to his left to cut off the ball and prevent a double, but he didn’t even attempt to throw home and was shocked no one moved.

“I was looking to see if [Ruggiano] was going to try to go first to third,” Span said. “I see him stop. That’s why I flipped the ball in. And I flipped the ball in and saw [Coghlan] didn’t go.”

Span got another chance on the next play with the bases loaded. Storen hung a slider, and Starlin Castro lifted a ball to center. Span caught it and fired toward the plate. Ramos collected the two-hop throw to the right of the plate and spun around. Coghlan slid head-first, and his left hand touched home under Ramos’s tag.

“Definitely not my best throw,” Span said. “But I got rid of the ball pretty quick. I assumed that he was going to tag. It’s one of those plays where it has to be a perfect play, so I see why they took the chance in tagging.”

The play meant Storen had allowed an earned run for only the fourth time in 32 appearances. The Cubs would have taken the lead an inning later if not for Tyler Clippard’s magic act. He created his own jam — a leadoff single by Schierholtz and then a walk of .184-hitting John Baker — but managed to wriggle out of it.

With one out, Clippard fired a gutsy 2-2 splitter right on the outside edge to strike out Welington Castillo looking. Clippard then got Ryan Sweeney to roll over a change-up for an inning-ending groundout. Clippard pumped his fist as he strutted off the mound, setting up the Nationals’ winning rally in the bottom of the inning. With Zimmerman’s pivotal hit, the gaffes and miscues were washed away.