Brad Mills-USA TODAY Sports

Jonathan Niese shouldered no blame for the deficiency he carried to the Nationals Park mound Friday night, a method ill-equipped for the task at hand. He had come to stop Jayson Werth and the Washington Nationals’ offense. Niese had no defense for the problem of throwing with his left arm.

Before Werth’s wall-banging catch, the Nationals prolonged their assault on southpaw starters, one Werth has waged for the better part of three years. Playing without three heart-of-the-order sluggers for most of the season, the Nationals’ offense can claim few superlatives. Battering left-handed starting pitchers is one, and no one in the majors does it as well as Werth.

Friday, Werth ended the Nationals’ 5-2 victory with a stunning catch to rob a game-tying homer. He also sparked the Nationals’ rare early outburst, a three-run first inning that blossomed after his RBI single. The Nationals finally grabbed an early lead instead of hanging one to their opponent. That it came against a lefty blunted the surprise.

Entering Friday, the Nationals had hit .283 and slugged .446 with a .337 on-base percentage against left-handed starting pitchers. They chased Niese after four innings, at which point they led, 5-0.

Werth began the scoring when, in his first at-bat, he smoked a single to left field. The Nationals led, 1-0, and Werth had collected his 15th hit in 33 at-bats this season against left-handed pitching. By the end of the night, after an out and a bloop single, his .457 average against southpaws led all National League hitters. It also displayed how Werth has evolved as a hitter during his four seasons in Washington.

In Werth’s first year with the Nationals, as he struggled to adapt to new surroundings, Werth batted .184 against left-handers, a departure from the rest of his career. Only three right-handed hitters were worse. No other factor affected his maiden season after signing a seven-year, $126 million contract worse. Werth studied film that offseason, discovered a defect in his swing and changed the path of his bat.

“It was very telling to me, and right on plane with where the flaw in my swing was,” Werth said in the spring of 2012. “If you look over the course of my career, I’ve been successful against lefties. Knowing what I know about my swing and knowing where I was, I was not surprised by the outcome as much. I knew what I was susceptible to. I knew where I was.”

In the three seasons since, has made himself a better hitter for average than he ever was in Philadelphia. He diagnosed and attacked a sudden weakness – his bat against lefties – until it became one of the fiercest weapons in baseball. Since the start of 2012, Werth has hit .383 against left-handed pitchers, second only to Andrew McCutchen.

“I’ve always felt comfortable against lefties,” Werth said.

Asked to elaborate, Werth chose to keep the answer to himself.

“I don’t want to give away too many secrets,” he said.

With so many Nationals landing on the disabled list, Werth has provided the brunt of what offense they’ve produced. As Ryan Zimmerman, Adam LaRoche, Bryce Harper and Wilson Ramos have missed time, Manager Matt Williams has penciled the same name into the No. 3 spot every day. Werth has responded with an OPS scratching of .834.

Tyler Moore has provided a boost at first base with LaRoche out – he actually the Nationals in WAR during May. Scott Hairston, who blasted a two-out, RBI double in the third Friday night, has also been pivotal. Playing left with Bryce Harper out, Hairston has gone 7 for 15 this year.

Hairston and Moore fit a similar profile as hitters, right-handed sluggers who can crush lefties. That fits with the rest of the Nationals.

“The middle of the lineup is right-handed,” Manager Matt Williams said. “That speaks well to the matchups against a lefty. But still have to have a nice approach and stay on the baseball. I think it’s good that we have a lot of guys that hit the ball to the opposite gap so when you’re facing a left-hander it helps to have that natural approach.”