NEW YORK -- Ryan Pressly needed only 18 pitches to remind everyone outside of his clubhouse just how valuable he is to Houston’s pitching staff.

The right-hander was the best reliever in the Astros’ bullpen during the regular season, the lockdown arm that could be called upon for a shutdown inning, and it didn’t matter whether the batters were right-handed or hit from the left side. Pressly would pitch in the seventh, eighth or ninth inning and never blink.

But a late-season right knee injury required surgery and changed everything. On Thursday night at Yankee Stadium in Game 4 of the American League Championship Series, Pressly changed it back in what will go down as one of the most important performances in his career.

The right-hander came into the game in the fifth inning with one out, two runners on and his club hanging onto a two-run lead. All Pressly did was shut down the Yankees and help pave the way to an 8-3 win that put the Astros on the cusp on returning to the baseball’s biggest stage.

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Houston is one victory away from returning to the World Series for the second time in three seasons, and the Astros are going to need Pressly and his bullpen mates to keep pitching like they did Thursday to get there and win it all again.

“It’s definitely up there,” Pressly said when asked where Thursday’s outing ranks among the best of his career. “It doesn’t get any better than pitching in the Bronx in the postseason. This is what you dream of as a kid, and I enjoyed every second of it.”

Astros starter Zack Greinke wasn’t at his best on Thursday, but he was effective for 4 1/3 innings. The right-hander walked in a run as part of an eventful first inning, but he rebounded. At one point, Greinke sat down eight Yankees in a row and 11 of 12 before giving up a one-out single to DJ LeMahieu in the fifth. Greinke walked the next batter, Aaron Judge, and that’s when Pressly came in to face Yanks center fielder Aaron Hicks.

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Teammate Carlos Correa had a few words of encouragement before the pitcher made his first delivery to Hicks.

“I told him, ‘This is your moment,’” Correa said. “I remember when we were in the training room both rehabbing at the same time. This is the moment that we worked really hard for, for moments like this, for moments for you to shine and give us a chance to win the ballgame.”

Pressly quickly fell behind 2-0 in the count and threw three consecutive curveballs to work the count full. He missed on his sixth pitch, a slider low and outside, to walk Hicks and load the bases for hot-hitting Yankees second baseman Gleyber Torres. The reliever peppered Torres with a steady combo of curveballs and sliders, eventually striking him out on a check-swing on a slider.

Did he go?

“I haven't looked at the replay,” Yanks manager Aaron Boone said. “I thought he did from the side.”

Torres concurred: “Yep. Sure.”

Two sliders and two strikes later, Yankees designated hitter Edwin Encarnación was in an 0-2 hole. Pressly buried him with his fastest pitch of the outing, a 94.5 mph fastball, to put him away four pitches later.

“I thought [Pressly] made some good pitches, mixed in both his curveball slider and threw some good fastballs in situations, too,” Boone said. “I think he did a good job of settling in and buckling down. We've had a little bit of success against him in this series, and then he made some pitches there to get out of an inning.”

Pressly’s job was done after the fifth, but more importantly, he resembled the workhorse who sported a 2.50 ERA and had a 33 percent strikeout rate in 50 1/3 innings before going on the injured list in late August. Before knee surgery, Pressly’s fastball averaged 95.7 mph. It dipped to 94.2 mph once he returned.

This postseason, Pressly’s fastball has averaged 94.7 mph; on Thursday, it ticked up to 94.8 mph with better command of all of his pitches. He threw eight changeups, six sliders and four fastballs in Game 4.

“I’m still working back to getting to be myself,” Pressly said. “It was tough coming back from the knee surgery. I developed some bad habits pitching on it for so long. I have to keep going out there. It’s all about repetition on the mound.”

As for Correa, he followed his own advice and hit three-run home run in the sixth to extend his team’s lead to 6-1. The shortstop had embraced the moment, but everyone in the Astros' clubhouse knew it was Pressly who played a big part in setting it all up.

“That [fifth inning] was huge, obviously, and I feel like that was the key of this game, that inning,” said closer Roberto Osuna, who pitched the final 1 1/3 innings. “[Pressly] has been unbelievable. He was our best arm all season long. He got the surgery, and he made it back. I don’t know where we would be without him.”

Pressly’s recent numbers don’t tell the entire story, but they do offer some insight into his progress. He has a 15.43 ERA in 2 1/3 innings in five appearances this postseason. Opponents have a .563 batting average against Pressly during that span. In three ALCS games, he has a 13.50 ERA with opponents hitting .556 against him in the 1 1/3 innings he’s pitched.

Pressly had plenty of help on Thursday. Relievers Will Harris and Joe Smith each struck out two batters. The lone blemish was a two-run home run by Gary Sanchez off Josh James in the sixth that cut Houston’s lead to 6-3.

“[Pressly] has been one of our guys that we've leaned on so heavily, but that was a really, really nice time of the game for him to come through big and feel back in the mix in a huge leverage spot,” Astros manager AJ Hinch said. “I was asked a lot about our bullpen coming into this series. The series is not over, but so far this series, our bullpen has been huge to complement a really good starting rotation.”