HOUSTON -- For much of the month of October, the Astros’ bullpen had risen to the challenge. Houston’s relievers came through with big outs in the American League Championship Series, beating a Yankees team that was said to have a superior bullpen. They were nails in winning the middle three games of the World Series in Washington.

The final two games of the World Series were an exercise in frustration -- and ultimately dejection -- for manager AJ Hinch, who watched his bullpen allow eight runs over 6 2/3 innings in home losses during Games 6 and 7 to the Nationals, who rallied late in Wednesday night's Game 7 to beat the Astros, 6-2, and win their first World Series.

A star-studded Houston team that was looking to win its second World Series title in three seasons came up one game short -- or three innings short in the case of Game 7. The Astros, riding a great start by Zack Greinke, carried a 2-0 lead into the seventh inning before the walls caved in on their pitching staff.

Greinke was pulled after 80 pitches, following a solo homer by Anthony Rendon and a walk to Juan Soto, and Will Harris -- who earlier in the Series was dubbed as Hinch’s “panic button” -- gave up a crushing two-run homer to Howie Kendrick that put the Nationals ahead, 3-2. It continued from there. Roberto Osuna gave up a run in the eighth and Joe Smith allowed a pair in the ninth.

• Harris' G7 loss was 'every reliever's nightmare'

The Nats danced and celebrated on the middle of the Minute Maid Park diamond, leaving the 107-win Astros wondering what-if. In the case of bringing in Harris, Hinch said it was a matter of matchups.

“Kendrick and [Asdrúbal] Cabrera was where I had really focused on Will Harris at that point,” Hinch said. “Will has been tremendous for us. I knew I had Osuna, I knew I had Gerrit [Cole], if need be. Will coming in to spin the breaking ball, he got the swing and miss, then he hit a ball off the foul pole in right field, and off they go.”

Greinke, who was acquired from the D-backs in a July move that most believe made the Astros the World Series favorites, had allowed only two baserunners through six scoreless innings. He was cruising.

“I was pitching good,” Greinke said. “They got a good lineup, especially the top of the order. It’s tough to get through no matter one time, two times, three times -- all of them. All of them are tough. Really good hitters up there.”

On the decision to remove Greinke, Hinch said it’s one he will have to live with.

“I'll think about it,” he said. “And I don't know what would have happened had I left him in. But that was kind of where I targeted based on where the game was going and what we had available to us.”

Hinch said Cole, who dominated the Nationals to win Game 5 in Washington, was warming up in the fifth inning, and he was prepared to bring him into the game at some point if the Astros took the lead. Instead, Cole sat with his sweatshirt pulled over his head and watched the Nats put the game out of reach.

“I wasn't going to pitch him unless we were going to win the World Series and have a lead,” Hinch said. “He was going to help us win. He was available, and I felt it was a game that he was going to come in had we tied it or taken the lead. He was going to close the game in the ninth after I brought Osuna in, had we kept the lead.”

It was a plan that the Red Sox used with ace Chris Sale to close out the World Series just last year, and Cole said he and Hinch had laid out the game plan, believing the most advantageous plan was using him with the lead.

“We didn't get the [opportunity],” Cole said. “It's not fun.”

When Cole emerged from Houston's dugout and walked out to the bullpen in the middle of the fifth inning, catcher Robinson Chirinos was sure he’d see him on the mound.

“I thought he was going to have a chance to pitch tonight,” Chirinos said. “He went down to the bullpen in the fifth inning and said, ‘I'll see you later today.’ I was waiting for him to come into the game.”

Harris, Osuna, Smith and Ryan Pressly -- all of whom pitched in Game 7 -- have been the Astros' most dependable relievers for much of the season, especially in the playoffs. Harris had been untouchable before allowing a homer to Rendon late in the Game 6 loss. Smith had three scoreless World Series appearances under his belt prior to Game 7. Osuna threw a scoreless inning in his only previous World Series outing in Game 3.

When the dust settled, Houston’s relievers had a 5.73 ERA in 22 innings in the World Series, which was about a run higher than their total for the entire playoffs (4.71) and about two runs higher than the regular season (3.75).

“You just don’t really know the outcome until you show up and you play the games,” Harris said. “They earned it. They beat us four times here, which is not easy to do. I just give them all the credit in the world.”