PHILADELPHIA -- Kyle Schwarber hit a leadoff home run on Saturday afternoon to set the tone for a performance unlike any he’s had before -- and for the Phillies’ first walk-off win of the season.

Schwarber played a key role throughout the 4-3 victory over the Pirates at Citizens Bank Park, which was capped by Nick Castellanos delivering a much-needed RBI single over a drawn-in outfield to walk it off. It was Philadelphia's first walk-off victory since Sept. 26 last season, also against the Pirates.

Two innings after igniting the game-tying rally with a leadoff walk against tough lefty Aroldis Chapman in the seventh, Schwarber set up the game-winning rally with a leadoff single in the ninth off another left-handed reliever in Jose Hernandez. Schwarber also went 2-for-2 with a homer and a walk against veteran left-handed starter Marco Gonzales.

"This guy can hit,” said Pirates manager Derek Shelton. “You're talking about a really elite hitter, a guy that's hit 40-plus homers multiple times. A guy that you cannot make mistakes against. I think we saw that today.”

Saturday marked the first time in Schwarber's career that he reached base five times against a left-handed pitcher in the same game. In fact, he had never even done it four times.

Schwarber also became just the third left-handed hitter in the past eight seasons to reach five times against a left-handed pitcher in a game, joining Anthony Rizzo (April 20, 2023, vs. the Angels) and Juan Soto (Sept. 7, 2021, vs. the Braves).

“I was able to see the ball well today, and I was able to get results,” said Schwarber, whose three hits each had an exit velocity well above 100 mph. “Results will come and go, but everything about it -- throughout the day today -- felt good, felt right. And it worked out.”

But it’s not just Saturday.

“Honestly, he's looked pretty locked in all season,” Castellanos said. “ … He's doing fantastic.”

Particularly (and surprisingly), against left-handers.

Schwarber is hitting .448 (13-for-29) with two homers and six walks against lefties this season. Obviously, it’s an incredibly small sample size, but this is the same guy who hit .191 with a .724 OPS against southpaws over his first two seasons with Philadelphia.

“I just think the biggest thing I want to find myself doing overall, in general -- doesn't matter [vs.] right, left -- is just swinging at balls in the zone and take the ones out of the zone,” said Schwarber, who is just 2-for-29 (.069) with 10 strikeouts against righties. “Being able to control the zone and be aggressive in the zone is something I want to focus on.”

Schwarber has certainly checked those boxes over the season’s first few weeks. Entering Saturday, his 19.1% chase rate would be the lowest of his career, while his first-pitch swing rate (32.3%) would be his highest. His overall swing rate (43.8%) would be his highest since 2017.

In other words, Schwarber is indeed laying off pitches out of the zone while simultaneously remaining aggressive against the ones in it.

And that’s not the only place he’s being aggressive. Following his seventh-inning walk, Schwarber went to second on a passed ball before advancing to third when he took off on a Chapman pitch that ultimately resulted in a Trea Turner groundout. Schwarber then scored the tying run on Alec Bohm’s base knock two batters later.

"He's smart; been around a little while. Veteran guy,” manager Rob Thomson said. “He has some savvy. He can do a lot of little things like that to help a club.”

Long before any of that, Schwarber's leadoff home run against Gonzales left the bat at 104.4 mph and traveled a Statcast-projected 424 feet to left-center field on a day when the wind was cranking from left to right. A few hours later, Schwarber had a chance to bookend his day with a walk-off home run, but he whiffed on two big cuts before shortening up to rip a 103.8 mph single into right field.

A few moments later, Schwarber, who was lifted for pinch-runner Whit Merrifield, was one of the first teammates to reach an elated Castellanos as they celebrated his first walk-off hit as a Phillie (and fourth of his career) on the infield dirt.

“It's a lot of fun when all your friends are running at you, man,” Castellanos said. “It's a good time.”