NEW YORK -- Without the snarl or the physique that creates an intimidation factor for many closers, Luke Weaver almost looked like he could have been blown off the Yankee Stadium mound by a medium-sized gust of wind when he stepped in for his postseason debut at the age of 31 on Saturday night.

Pitching for the most tradition-rich team in his sport at the most pressurized time of year, the unlikely closer -- a role he had no experience with in his first eight MLB seasons, or even until Sept. 6 of this season -- the righty never blinked.

Not when he came on with two outs in the eighth inning and the tying run on first base and got a big strikeout; not when he fell behind 3-0 to the dangerous Bobby Witt Jr. with one out in the ninth and came back to strike him out looking; and not when it was time to cue up Frank Sinatra on the stadium speakers by retiring Vinnie Pasquantino for the final out of a 6-5 victory over the Royals in Game 1 of the American League Division Series.

When Clay Holmes faltered down the stretch and had to be taken out of ninth-inning duties by manager Aaron Boone for the final month of the regular season, it was fair to wonder who would step up.

Wonder no longer. Weaver converted all four of his save chances in September, a dominant month in which he had 25 strikeouts over 12 innings, holding opponents to a .438 OPS.

The evolution of Weaver’s stuff that has led to this breakout season has been chronicled in recent weeks.

But you can never be sure how a pitcher -- especially one who wears pinstripes -- will handle October until he gets there.

If first impressions are any indication, Weaver looked ready for the role on Saturday, retiring all four batters he faced.

The list of Yankees relievers to get a save of four-plus outs in a postseason debut is short, and had to be dusted off for the first time in three-quarters of a century -- since before saves were an official stat -- thanks to Weaver’s effort on Saturday. Here it is:

Wilcy Moore, 1927 WS Game 1 at PIT (1 2/3 IP)
Johnny Murphy, 1936 WS Game 6 at NYG (2 2/3 IP)
Joe Page, 1947 WS Game 1 vs. BKN (4 IP)
Luke Weaver, 2024 ALDS Game 1 vs. KC (1 1/3 IP)

How has the closer who had never closed become so equipped to handle the highly pressurized role?

“Well, it’s sure not my size and my physique, even though I feel like being wiry gives me a very internally strong foundational attribute,” Weaver said. “I feel like I'm pretty chill personality-wise. Just growing up and playing this game, the [past] failure just builds up kind of an iron wall.”

If Weaver doesn’t look like the central casting version of a closer, his teammate Jazz Chisholm Jr. has seen things behind the scenes that led him to believe in the righty.

“Every time since I've been a Yankee, I've sat on the [other] side of him on the plane and he's built for it,” said Chisholm. “I know nobody sees it in his attitude, but if you really go and watch him go out there and you just get to know him a little bit more, he's built for that moment. He could be playing cards and he’s a dog. His mindset in every competition that he goes into is that he's gonna win, and he's gonna do it his way.”

The Yankees have a history of closers who have embraced October, including Sparky Lyle, Goose Gossage, John Wetteland and the standard-bearer in Mariano Rivera.

But none of them had a path as unlikely as the one taken by Weaver, who was a journeyman starter and reliever and originally came to the Yankees as a waiver claim from the Mariners on Sept. 12, 2023.

Weaver re-upped with the Yankees as a free agent on Jan. 11 for a one-year $2 million contract that includes a $2.5 million option which is now a no-brainer.

His reasoning to return to New York after his brief stint last year was with nights like Saturday in mind.

“I just got tired of waiting,” said Weaver. “I got here for many reasons, but the reason is to try to win, to go deep into the playoffs, first and foremost, and just be there -- not watching it on TV. It’s everything you dream of. It’s all the clichés mixed into one. But it truly does mean something and I hope it continues.”

Somehow, the moment lived up to his expectations.

“I could feel the electricity,” Weaver said. “I could feel the major things that one would feel out there, one being adrenaline. But it was really cool. It was an amazing game. It was a heck of a game to be a part of, to watch, and then to go out there and try to make sure we cap it off. It's definitely a core memory.”

• Yanks come back to win historic back-and-forth affair

To become the truest of Yankees, Weaver realizes he will need to add plenty of more memories in the coming weeks.