CLEVELAND — Aaron Boone showed no fear in going to his bullpen in the fifth inning in the Yankees’ Game 2 win in the ALCS, even with Gerrit Cole on the mound.

And once again, the pen delivered, this time allowing just one run over 4 ²/₃ innings, with four different relievers contributing.

Through six games this October, the Yankee pen has been tested often — and passed every time.

Luke Weaver has solidified the Yankees’ closer role since being put into the spot in September.Jason Szenes / New York Post

They’ve allowed three runs — two earned — in 23 ¹/₃ innings, with a WHIP of just 0.857 and helped make up for some brief outings from the rotation.

Luke Weaver, Clay Holmes, Tommy Kahnle and, on Tuesday, Tim Hill have gotten multiple huge outs for the Yankees in tight situations.

So far, at least, the performance harkens back to some of the Yankee championship teams that featured intimidating bullpens that hardly ever faltered this time of year.

Holmes, as dominant as any reliever in his time in the playoffs with 14 ²/₃ scoreless innings in a dozen career appearances, is aware of the great Yankees teams that featured excellent bullpens.

“There’s a lot of history here with really good teams and the bullpens have been a big part of that,’’ Holmes said. “We know the challenge and opportunity we have here to be part of something special.”

They still have a long way to go to cement themselves in Yankee lore, but they’ve gotten to within a pair of wins of getting back to the World Series for the first time since the team’s last title in 2009.

Clay Holmes, who was demoted from the closer’s role in September, has thrived in all the other high-leverage situations throughout these playoffs.Jason Szenes / New York Post

There’s no bigger reason they’ve made it this far than the bullpen, and a member of one of those championship pens has been impressed by this current group.

Jeff Nelson won four World Series rings in a five-year span with the Yankees as part of a Mariano Rivera-led bullpen.

“No one can compare to Mo,’’ Nelson said by phone Wednesday, “but it’s pretty remarkable what these guys are doing.”

Tim Hill gets some congratulations from Austin Wells during his strong relief stint in the Yankees’ Game 2 win over the Guardians.Corey Sipkin / New York Post

He’s been especially impressed by how the key members of the pen have thrived in different roles — including roles they were unaccustomed to until late in the regular season.

“The fact they didn’t have a set closer late in the year and then Weaver steps up, with Holmes, Kahnle and even Hill and Cousins filling in a lot of roles,’’ Nelson said. “They’re asking a lot of them and it’s fair to compare what they’re doing to some of our playoff runs, but we did it for a long time.”

And Nelson’s pens also finished the job with title after title.

They’ve done it with one setup man, Holmes, who lost the closer job earlier in the season and a closer in Weaver who had never done the job before.

Longtime bullpen coach Mike Harkey, who was around in 2009, said Wednesday of Holmes, “He’s been one who’s really taken to the old Mariano adage, where if he’s going to be a closer or a late-inning, high [leverage] relief pitcher for the Yankees, he’s going to have to have a short memory, and that’s what he’s been able to do since he’s been here.”

Tommy Kahnle has had a strong playoffs for the Yankees.Jason Szenes / New York Post

And Harkey noted on a Zoom call from the Stadium that while Rivera was the greatest closer of all time, Weaver has as many saves this postseason — four — as he did in his career heading into the playoffs.

This group remains two wins shy of getting to the World Series, but Nelson appreciates what they’re in the process of doing — particularly with the Yankees not getting much length out of their starters.

“It’s impressive, because you can’t go with matchups anymore,’’ Nelson said of the fact that relievers are forced to face at least three batters in an appearance. “And our starters usually went deep and now they have to get 14 or 15 outs a lot.”

Still, certain aspects remain the same and this group of relievers has been up to the task.

“It takes a certain mentality to pitch well this time of year,’’ Nelson said. “There’s no tomorrow in the playoffs. You can’t have any hiccups and you don’t know how guys are gonna do until they get there. These guys didn’t have much experience, but they’re getting the job done.”

“We feel like everyone is confident in us down there and they all feed off of it,” Holmes said. “You scratch some runs up early and let us finish. It’s working so far.’’