BOSTON -- In the aftermath of MLB’s past two World Series champions facing off for the first time this season, the man who won rings with both squads took accountability for the way the riveting contest ended up.

While the Astros rode George Springer's two-run rocket to a 3-1 win over the defending World Series champions, Red Sox manager Alex Cora felt he let his team down.

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The way Cora looks at it, righty starter Rick Porcello -- who turned in a mostly fantastic performance -- shouldn’t have stayed in to face Springer for that key at-bat in the top of the eighth.

“That was a bad decision,” said Cora. “That was a bad one from the get go. I mean, that’s the best lineup in baseball. He goes seven, and every pitch is high-leverage. He did his job, you know? The whole thing about one hitter and get him out, what’s the point? We have the best player in baseball right now with a man at second and no outs, that’s on me. That’s not on Rick. I just made a bad decision, put him in a bad spot, and we paid the price.”

To set the scene, Porcello had thrown 92 pitches through seven and hadn’t given up a hit since the second inning. He was in possession of a 1-0 lead.

Jake Marisnick opened the game-turning frame with a double.

Up stepped Springer, who has tormented Porcello through the years. That tormenting continued as Springer jumped on his first-pitch fastball and hammered it over the wall in right-center for his 17th homer of the season. Only this time, Cora is the one who felt tormented.

“Should have taken him out after seven,” Cora said. “It’s not because of what happened. I just put him in a bad spot there.”

Including postseason play, Springer improved to 10-for-19 with three homers against Porcello lifetime. Not that you needed to tell Cora. He was fully aware.

“Obviously, I don’t get a mulligan,” said Cora. “I don’t. But he did an outstanding job for seven against the best lineup in baseball. It’s not about facing the lineup for the fourth time or whatever, it’s [more] like, every pitch against them is a high-leverage situation. You have to execute and change speeds and keep the fastball around the plate. It’s not an easy lineup to maneuver, and he did it.”

According to Porcello, however, this loss wasn’t on the manager.

“That’s on me in the eighth inning,” Porcello said. "I threw the two worst pitches of the night to back-to-back hitters, back-to-back pitches. And that was the result. I’ve got to do a better job. AC trusted me to go out there in the eighth inning and I’ve got to make better pitches at least. If they hit those then fine, but those were cookies. So it’s a tough loss.”

Ryan Brasier was warming in the bullpen when Cora stuck with Porcello. And perhaps the decision would have been easier if Brasier was pitching like he did last year. But the righty reliever has struggled in recent weeks.

In his last six outings, Brasier has given up six hits, four walks and seven runs (five earned), including the unearned insurance run after Porcello departed on Friday night.

“Just trying to find it,” Brasier said. “I have been struggling a little bit, but just have to keep grinding and get back to what I do best.”

The Red Sox still had a chance to win it in the bottom of the ninth when reigning AL MVP Award winner Mookie Betts stepped up with two on and two outs against Astros closer Roberto Osuna. With the Fenway crowd loud with anticipation, Betts hit a liner with a 107.4 mph exit velocity to left that had an expected batting average of .740, according to Statcast. But left fielder Michael Brantley snagged it to end the AL heavyweight battle.

“Yeah, it seems like we’re always playing good games against them and tight ballgames,” Porcello said. “They’re a fantastic club. They’ve got it all the way around. I think we have it all the way around. Makes for a good matchup.”

Prior to the game, Cora tossed deserved praise toward the team he won the World Series with as bench coach in 2017.

“I think right now [they’re] the best team in the big leagues,” Cora said.

The 23-21 Red Sox still have 118 games left in the regular season to re-establish themselves as the best team. But right now, the Astros have earned that label Cora bestowed upon them both with their MLB-best record (30-15) and the way they execute.

Either way, these two teams could be on a collision course to meet in the postseason for the third straight year.

“The atmosphere was great until the eighth for me,” quipped Cora. “And it was great in the ninth. I always say you have to be accountable, transparent and responsible. I ask that from my players and I’m the same way.

“But it was fun. They’re a good baseball team, but we’re good too. We know we can play. We’ve played better [lately]. There was traffic all over the place. We ran the bases well. We played good defense. It just happened they scored those three runs in the eighth.”