PITTSBURGH -- Had Ke'Bryan Hayes been in the No. 2 spot in the lineup, as he¡¯s been for the majority of 2021, he never would have stepped to the plate with two outs in the ninth inning against the Nationals on Friday.

But he¡¯s batted in the leadoff spot in each of his past five games, and that one-spot jump allowed him an at-bat against Nats reliever Patrick Murphy with Ben Gamel on third base.

True to his style of offense, Hayes stroked an opposite-field ground ball down the first-base line to cap a 4-3 walk-off win at PNC Park in the series opener.

It was the first walk-off winner of Hayes¡¯ career and, he believes, the first since his senior year of high school.

The Pirates have crushed some walk-offs this season, including Jacob Stallings¡¯ blast to down the Mets, but Hayes knew what to do on Friday with a runner 90 feet away.

¡°I wasn't trying to do too much,¡± Hayes said. ¡°A single was going to win the game, so I was just trying to hit something low and hard.¡±

The ball was definitely low (-1 degree launch angle) and fairly hard (90.8 mph exit velocity), but most of all, it was perfectly placed. Former Pirates first baseman Josh Bell didn¡¯t have a chance to corral it and save the Nats, as he nearly did with a home run off Sam Howard in the sixth inning.

That dinger, to the notch in left field, would represent the only run the Pirates¡¯ bullpen gave up over seven innings, though. Starter Steven Brault exited with left arm discomfort after two innings, an unfortunate development after he'd made only six starts this season, but the relief corps had a much-needed off-day on Thursday and looked refreshed on Friday.

Cody Ponce followed Brault with three hitless innings to lead the charge. What was working for him?

¡°[Catcher] Jacob Stallings was working for me,¡± Ponce said. ¡°When I called him out, he asked me what I wanted to throw. I said, ¡®Whatever you want to call. I trust you, and I love you. Let¡¯s just go back to work.¡¯¡±

The plan Stallings drew up included a strong cutter, which manager Derek Shelton made a note to mention after the game, but Ponce carried the way with strong fastball command, including an inside heater that got a rare strikeout looking from Nats slugger Juan Soto.

Howard allowed the one run to Bell in two innings, then birthday boy Chad Kuhl and Nick Mears matched each other with a scoreless inning each. After a trip to Chicago that featured six straight losses and poor bullpen stats, it was reassuring to see them step up in such a big way. But Shelton believes the Chicago trip doesn¡¯t tell the story of how well his relievers have thrown the ball.

¡°??They didn¡¯t pitch as bad as their lines were, because we didn¡¯t catch the ball,¡± Shelton said. ¡°And I think one of the things that makes your pitchers good is when you play good defense. And we¡¯ve played good defense on this stretch.¡±

Good pitching and good defense gave the Pirates their chance in the ninth after scuffling against Nationals starter Josh Rogers, who pitched into the seventh inning with only two runs to his line in his fifth Major League start.

And that gave a big opportunity to a batter who has been through fairly short peaks and fairly long valleys throughout the season. Hayes entered September with an injured right hand -- hurt in a moment of frustration when he slammed his helmet -- along with a .246 average and a .647 OPS.

Now he is 9-for-19 for September, although there¡¯s still a lot of work to be done. Shelton said that Hayes still has to do some work to get to his pull side and complement his line-drive approach to center and opposite fields.

But Shelton learned something important about his leadoff rookie on Friday and how he handles adversity to persevere and produce a walk-off win.

¡°I think the big thing was, for a young kid, he didn¡¯t let the moment get too big, and he just stayed with his approach and drove the ball that way,¡± Shelton said.