BOSTON — Brent Strom’s father, Chester, grew up in Worcester, Mass., some 45 miles west of Fenway Park. Chester raised his son in San Diego but passed on his love of the Boston Celtics, who reigned atop the N.B.A. when Brent was young.

Brent Strom, now 73, would go on to a long career in baseball, pitching five seasons in the majors and coaching for many more. Now he guides the bruised and battered pitching staff of the Houston Astros, who tied their American League Championship Series with the Boston Red Sox on Tuesday, two games apiece, with an effort out of Red Auerbach’s playbook.

When Strom was 10 years old, he explained, he would open the sports section of the local paper and see two columns on the N.B.A. page: standings on the left, leading scorers on the right. The Celtics always led the left row, but rarely seemed to have a player in the top 10 on the right. Invariably, the stars of the Stroms’ favorite team — Bill Russell, Bob Cousy, Bill Sharman, Tommy Heinsohn — would be clustered in the teens.

“Why is that?” Brent would ask his father.

“They play as a team,” Chester would reply.

Which brings us to Game 4 of the A.L.C.S., when the Astros’ starter, Zack Greinke, allowed a two-run homer in the first inning and left with one out in the second. It would take extraordinary teamwork to win, but the Astros’ bullpen was up to it.

Five relievers — Brooks Raley, Cristian Javier, Phil Maton, Kendall Graveman and Ryan Pressly — unplugged Boston’s surging offense the rest of the way. Their effort gave the Astros a chance to tie the game in the eighth and blow it open in the ninth in a 9-2 victory.

“I think that was the real key to winning the game, the way they pitched,” said second baseman Jose Altuve, whose rocket over the Green Monster tied the game in the eighth. “I know we scored some runs at the end, but they kept the game close all the way, and that’s what we needed.”

The Red Sox have torched the Astros’ starters this series for 16 runs (14 earned) in just six and two thirds innings. That comes out to an 18.90 earned run average — with 14 hits allowed, 11 walks and five strikeouts — for the rotation of Framber Valdez, Luis Garcia, Jose Urquidy and Zack Greinke.

It is a ghastly stat line for a group that lost its ace, the right-hander Lance McCullers Jr., to a flexor pronator strain during the division series. Garcia hurt his knee in Game 2, and Greinke, who was slowed in September by Covid-19 and neck soreness, had not started in a month.

It showed. Greinke, who turns 38 on Thursday, has faced more hitters in his career than any other active pitcher — but saw just nine on Tuesday. Strom said the Astros did not expect him to go much deeper, following the new and unsettling pattern of a team once loaded in durable, dominant starters.

“I always harken back to Rick Pitino,” Strom said, referring to the celebrated coach who could not revive the Celtics in the late 1990s. “When they were struggling, he basically voiced: there’s no McHale, Parish or Bird walking through that door. I’ve been unbelievably fortunate to have Verlanders and Coles and Keuchels and Mortons and all of these kinds of guys throughout the years here.”

But Justin Verlander missed this season recovering from Tommy John surgery, and the others Strom named have moved on: Gerrit Cole to the Yankees, Dallas Keuchel to the Chicago White Sox, Charlie Morton to the Atlanta Braves. Without them, the bullpen may continue bearing the burden of postseason survival.

“You have to face it head-on, but I think that moving forward our starters are going to be great,” said Graveman, adding later, “The conversation in the bullpen is if we need to pick someone up, we will. I think today was a telltale sign of that. Keeping our team close and Altuve hitting a big home run to tie it, and then putting up a bunch of zeros. So the conversations can’t be complaining. Whoever gets the job done, it’s just going to the next guy and passing it down.”

Graveman and Javier will not be available for Game 5 on Wednesday, Strom said, but Garcia will be, as will Ryne Stanek and Blake Taylor, who rested on Tuesday. Strom said the team would need Pressly again on Wednesday, even though he threw 22 pitches to close Game 4.

The way this series has played out, the Astros’ late-July trades for Graveman (from Seattle) and Maton (from Cleveland) look even more essential. Both pitchers have thrived in October, combining with Javier, Pressly, Stanek and Taylor for a 1.11 postseason E.R.A. in 31⅓ innings. They patch games together as best they can.

“That’s all we can ask,” Strom said. “And eventually with these young starters, if you look at the youth, with Framber and all these guys, they pitched well last year, but what were we missing? You had nobody in the stands. There wasn’t the energy that you see. So this is only going to benefit them down the road.”

The road will end in Houston for this A.L.C.S., with Game 6 on Friday and a potential Game 7 on Saturday. If the Astros win the American League championship, their relievers should hoist the trophy — as long as they can still lift their weary arms.