Jordan Zimmermann moved into a tie for the National League lead with his 15th victory. (Charlie Riedel/Associated Press)

Jayson Werth greeted Jordan Zimmermann and told him to watch the tape. The rest of the Washington Nationals’ clubhouse celebrated their fifth straight victory, a 7-2 win over the Kansas City Royals that kept them on the periphery of the playoff picture. Werth, reduced to spectator status, had told Zimmermann he had thrown perhaps his nastiest slider of the season. “So,” Zimmermann said, “I wanted to see what it looked like.”

Zimmermann plopped himself in front of a monitor and queued up the first inning: no one on base, two outs, Eric Hosmer batting. Zimmermann knew Hosmer had timed his fastball, and so he threw a “backfoot” slider. The pitch started inside and darted at Hosmer’s left ankle. Hosmer stabbed at the ball like a child trying to catch a firefly in a jar. He lifted his foot off the ground as he whiffed.

“I’m not real sure why he swung at it,” Zimmermann said. “It almost hit him in the back foot.”

It was that kind of night for Zimmermann at Kaufman Stadium. He allowed two runs over 72 / 3 innings for his 15th win, which tied him for the National League lead. The Nationals backed up their 11-run onslaught Friday even without red-hot Werth, who sat out with a troubling infection in his right foot. They scored four runs in the fourth inning with the help of an ill-fated intentional walk, and Ian Desmond blasted a two-run homer in the sixth.

The ninth inning provided welcome boredom, a 1-2-3 performance by Tyler Clippard. Spooked by a recent string of horrific final innings, Manager Davey Johnson used his best reliever despite a five-run lead with the bottom of the Royals’ order due up.

“I wasn’t taking any chances,” Johnson said. “I wanted to ice that one down.”

The night before, Johnson had yanked Drew Storen two batters into the ninth. He could tell from the glare Storen gave he was angry, and Johnson did not care. Victory, for him, took precedent over feelings.

“We’re in a pennant race, man,” Johnson said Saturday afternoon. “It’s time to get some energy flowing. I’m in my pennant mode now. We got to win every ballgame.”

The Nationals, really, are only on the edge of a pennant race, 81 / 2 games behind the Cincinnati Reds for the National League’s second wild-card spot with 33 games left. But they have not faded all the way to black.

Their fifth straight win matched a season high and made them 11-4 in their past 15 games, during which time they have scored 5.7 runs per game. After Sunday, the Nationals’ next 19 games will come against the eminently beatable New York Mets, Philadelphia Phillies and Miami Marlins. They need more help than they count on, and time is an enemy that may already have won. And yet meaningful September baseball is not out of the question.

“It’s just been a matter of time,” Desmond said. “We’re starting to get hot.”

They just need to keep winning almost every night. On Saturday, they relied on Zimmermann and an offense finally approaching the standard it set in 2012. Zimmermann had been rocked Tuesday against the Chicago Cubs, which raised his ERA over 10 starts since July to 5.96. He had nibbled with too many offspeed pitches, and “that’s not the way I pitch,” Zimmermann said.

He attacked the Royals early with his fastball. Their aggressive bats poked singles through the infield, and he wanted to turn the aggression against them. He induced a double play from Billy Butler in the third on a change-up. The rest of the night, he threw more change-ups — and better change-ups — than he had all season.

“I had four pitches working,” Zimmermann said. “And when I have that going, it’s going to be a fun night to be out there.”

For the second straight night, the Nationals seized control in the fourth inning. Ryan Zimmerman led off with a walk, and Bryce Harper smacked his second hit off Royals starter Wade Davis, a single to right. Wilson Ramos lifted a sacrifice fly to right field, which gave the Nationals a 2-1 lead.

After Desmond flied to center, Davis had a chance to squirm out of the inning with the Nationals ahead by only one run. Royals Manager Ned Yost ordered an intentional walk of Adam LaRoche, who walked to the plate batting .200 since the all-star break. Yost preferred Davis face right-hander Tyler Moore, who had been recalled this week and started only because Werth couldn’t play.

“I would have walked him, too,” Moore said. “He’s a good hitter.”

Moore stroked a 1-1 curveball off the left-center field fence. Harper scored to make it 3-1. LaRoche could make it only to third. When Chad Tracy blooped a single to shallow left, the hitter Yost intentionally walked and the one who made him pay both scored. The Nationals led, 5-1.

Moore’s struggles this year twice earned him trips back to Class AAA Syracuse, but he has improved in his third stint, albeit in a microscopic sample. Moore added a single in the ninth, which made him 11 for 21 since he returned this week. In his recent stint in Syracuse, he fixed a timing issue with hitting coach Troy Gingrich. Moore loaded his hands earlier, giving him more time to recognize pitches.

“It’s kind of slowing the ball down a lot,” Moore said.

Desmond added his 18th home run in the sixth, even if Zimmermann didn’t need it. Reliever Fernando Abad needed to squirm out of a bases-loaded jam in the eighth, but in the ninth Johnson could finally relax. The Nationals’ own misdeeds this season have kept them out of a real pennant race, but they have played well enough lately to keep alive the chance they may yet creep into one.