LOS ANGELES -- It was a last-minute decision in the right-field pavilion. The Dodgers had a four-run lead, it was the bottom of the eighth inning and Agustin Nuno figured this was his last chance to check out the postseason merch. He left his section of seats via a stairway behind the stadium’s outfield wall.

It was also a last-minute decision in the Dodgers’ dugout. Gavin Lux believed another rookie, Matt Beaty, was poised to pinch-hit in the pitcher’s spot. When manager Dave Roberts pointed to Lux instead, the 21-year-old didn’t have time to ponder the weight of the moment.

So, Lux stepped to the plate and Nuno stepped down those stairs. Their stories intertwined when Lux lined a home run right to that spot.

“It fell into a trash can,” Nuno said. “I just dove in there. I said, ‘Forget it, man.’

“Don’t tell Gavin.”

After the game, a commanding 6-0 Dodgers win, the two met outside the clubhouse. Lux signed a couple of clean baseballs in exchange for the one Nuno had spared a trip to landfill.

For both, it was a memorable night.

“I was just glad to be a part of it,” Nuno said.

Lux, the Dodgers' Minor League Player of the Year and one of four rookies on L.A.'s postseason roster, delivered the first of two Dodgers homers in the eighth as they extended a lead against Washington's shaky bullpen. Two batters after Lux came off the bench and took right-hander Hunter Strickland deep, Joc Pederson took Strickland even deeper, lofting a home run high off the right-field foul pole for a six-run lead.

Pederson has done that before. For Lux, it was a first, and for the Dodgers’ dugout, a chance to celebrate.

“It was a laser,” said Dodgers regular-season home run leader Cody Bellinger. “I was actually downstairs watching and we heard the crowd. Then we saw the velo [108 mph off the bat, according to Statcast] and that it was 21 degrees, and we thought, ‘There’s no way that’s a homer.’ He’s just showing what he can do. He’s kind of got the confidence like you wouldn’t know he just came up.”

“He didn’t look like a 17-year-old, or whatever he is,” Dodgers veteran Justin Turner quipped.

At 21 years, 314 days old, Lux is the fourth-youngest player in MLB history to homer in his postseason debut. Only Jimmy Sebring (1903), Brian McCann (2005) and Rougned Odor (2015) were younger.

Lux earned a September callup after combining to slash .347/.421/.607 with 25 homers for Double-A Tulsa and Triple-A Oklahoma City in 2019. He's ranked as the club's top prospect and No. 2 overall by MLB Pipeline, having risen fast through the ranks since the Dodgers drafted him 20th overall in 2016 out of Kenosha, Wis., where he played for the same travel program that recently produced Mariners Prospect of the Year Jarred Kelenic and D-backs No. 5 prospect Daulton Varsho.

Last October, Lux attended three of the NL Championship Series games between the Dodgers and Brewers at Miller Park, including the Game 7 win that punched the Dodgers’ World Series ticket. This October, Lux is on the Dodgers’ postseason roster. He got the news Wednesday in a meeting in Roberts’ office.

“If you would have told me four months ago I would be playing in the postseason, I probably wouldn’t believe you,” Lux said. “Very surreal moment, what every kid dreams about. Just really cool.”

And when he was pointed toward home plate for his first postseason at-bat?

“I didn’t really have enough time to, like, really process it,” Lux said. “It was just kind of get up there and go hit. Honestly, I wasn’t too nervous. I was more just excited to be out there and try to make something happen. It was cool.”