Jayson Werth hit his fourth game-winning RBI of the season to cap the Nats’ series in Colorado. (Garrett Ellwood/GETTY IMAGES)

During his first season with the Washington Nationals, even as their highest-paid player and even in the most vital moments, Jayson Werth has rarely wavered in his disciplined approach in the batter’s box. He places more importance on reaching base than any other offensive skill, and he will not allow the game situation to bend his attitude. He’ll take the walk.

Sunday, Werth made an apparent exception in the most crucial moment of the Nationals’ 3-2 victory over the Colorado Rockies. In the eighth inning, Werth eschewed patience and smacked the go-ahead single with a swing fit for the golf course. He hooked a slider below the knees into left field, giving him only his fourth game-winning RBI this season and the Nationals a series split in Colorado.

“It seems like the better I feel, the more aggressive I am,” Werth said. “The last couple weeks, I’ve felt pretty aggressive. I’ve also felt pretty good out there.”

Several performances set up, and then sealed, Werth’s game-winning single. John Lannan allowed one run in six-plus innings before a seventh-inning Rockies rally spoiled his shot at the win. Jonny Gomes crushed his first home run as a National, a two-run blow off Rockies starter Aaron Cook that served as the Nationals’ only offense before Werth struck in the eighth. Todd Coffey rebounded from recent struggles to pitch a scoreless eighth.

Perhaps most impressive, Drew Storen retired the heart of Colorado’s lineup in order in the ninth, closing with a strikeout of Troy Tulowitzki for his for his 29th save. Storen began Tulowitzki with a slider, worried that he may “ambush” a fastball and tie the score with one swing. He got ahead 0-2, and Tulowitzki fouled off two pitches and took a ball.

Storen fired his final pitch, a 96-mph fastball on the outside corner, right at knees. Tulowitzki watched it for strike three. (“Filthy,” Manager Davey Johnson said.) As Tulowitzki turned to talk to the home plate umpire, Storen pumped his fist, an uncommon show of emotion for him.

“It’s Tulo,” Storen said. “He’s an unbelievable hitter. It was just a battle. That was one of the most fun at-bats of the whole year. He’s an unbelievable hitter. I wanted to throw that pitch, and I got lucky and executed it. Because if I miss with that pitch at all, he hits it out. That’s what I live for right there.”

But the most pivotal moment, the one that allowed the Nationals to enjoy their flight to Chicago, came in the eighth inning. Danny Espinosa roped a leadoff double over left fielder Eric Young Jr.’s head. He moved to third on Ryan Zimmerman’s groundout, and Rockies reliever Matt Belisle intentionally walked Michael Morse to bring Werth to the plate.

Belisle threw Werth four consecutive fastballs. Werth fouled two off, swung at one and missed, and took another for a ball. He felt late on Belisle’s fastball, which hummed at 92 and 93 mph. He considered starting his swing earlier, but instead trusted himself to foul away another fastball if need be.

“After he threw the heater up, I made the decision I wasn’t going to change,” Werth said. “If I speed up to hit the heater, I’m probably susceptible to the slider. It was a stand-pat situation. I felt that was best chance.”

And with the count 1-2, Belisle threw Werth an 85-mph slider that broke beneath his knees. Werth kneeled down and served the ball into left field. Espinosa scored, giving the Nationals the last run they needed.

Werth considers himself a good low-ball hitter, part of the reason he swatted Belisle’s slider. But his recent surge has also given him confidence to swing more freely. Since the all-star break, Werth has a .370 on-base percentage while slugging .449.

“I think all year long, he’s been a little too passive,” Johnson said. “I like him more aggressive, and he’s getting more aggressive. That’s a good sign.”

The Nationals played for most of the game with a two-run lead, thanks to Gomes’s two-run blow in the second, a cutter he smoked about 20 rows deep to left field. The Rockies tied it with a two-run rally in the seventh, started when Lannan walked his last hitter with a 3-1 change-up. “I regretted it as soon as I threw it,” Lannan said. “It’s just awful pitching.”

For most of the day, though, Lannan provided the opposite of awful. Despite nine runners clogging the bases, Lannan allowed no runs in his first six innings. He relied on his four-seam fastball, his usually trusty two-seamer not sinking in the thin air. Lannan pitched well, and he also cleared a mental hurdle.

With two outs, Tulowitzki singled to put runners on the corners, bringing on Ty Wigginton. On July 8 at Nationals Park, Wigginton ripped a line drive that hit Lannan in the face, bloodying his face and forcing him from the game.

On Friday, Rockies pitcher Juan Nicasio was hit by a line drive and carted off the field with a fractured vertebra. Saturday, Lannan did not want to discuss the connection between his incident and Nicasio’s out of respect for the severity of Nicasio’s condition, and perhaps to help keep the potential danger of his profession out of his mind.

“Seeing what happened to that kid, you never want to see that,” Lannan said after the game. “Looking back on my situation, I’m lucky that what happened to me was only that. Things could be much worse, obviously. I just try not to think about it too much.”