Kimbrel walked Tony Kemp to load the bases, bringing the ever-dangerous Alex Bregman to the plate. Cora -- who had his Game 5 starter, David Price, warmed and ready in the bullpen -- watched from the dugout as Kimbrel prepared for the most important at-bat of the night.
"He's our guy," Cora said. "We've been talking about it the whole season. I know people were really anxious, 162 games and the first series, but we knew all along that something like this was going to come up and we trust our guy."
Kimbrel rewarded Cora's faith in him, getting Bregman out on a sinking liner to left, where Andrew Benintendi made a diving catch to end the game and move the Red Sox within one game of the World Series.
What was going through Kimbrel's mind as Bregman's ball headed for Benintendi in left field?
"Catch it," Kimbrel said. "He put a good swing on it. It's one of those balls that's an in-betweener; the way he was able to come in and lay out there, it took everything. It took everything we had. That's the kind of team we have.
"I gave him a big hug. He might get a big Christmas present."
Cora has remained steadfast in his confidence in Kimbrel, despite a shaky postseason in which the closer has saved all four games in which he's appeared, while giving up at least one run in each outing.
Kimbrel entered the game in the eighth ahead by three, but the Astros scored a run to cut the lead to two. Things might have been hairier had Kemp not tried to stretch his hit into a double, getting thrown out at second by Mookie Betts to open the inning.
"I didn't love it," Astros manager AJ Hinch said of Kemp's decision. "Down by three, it's a tough gamble."
With Price hot in the bullpen, Kimbrel came out for the ninth and walked a pair of hitters with one out. He retired Brian McCann on a fly ball, then saw Cora heading to the mound.
"He had his mind made up that he was going to keep me in," Kimbrel said. "I really appreciate that."
Kemp drew a walk to load the bases, but despite his 10.80 ERA through his first three appearances, Kimbrel wasn't forced to watch someone else clean up his mess as Bregman strolled to the plate.
"It means [Cora] trusts me," Kimbrel said. "I'm not necessarily throwing up the numbers and throwing clean innings, but I've been able to work through them. I have a lot of great defense behind me. The guys have been helping me out; the catches have been unbelievable. Things can turn around real fast. I'm glad he was able to stick with me and I was able to get it done."
Had the Astros moved one run closer in the eighth or ninth, that trust wouldn't have been enough for Cora. The manager told himself that as long as the lead was more than one run, Kimbrel was his guy. Otherwise, Price would have gotten the chance to be the hero out of the bullpen, a role he played to perfection for the Rays during the 2008 postseason.
"He was going to come in in the eighth if it was worse than what it was; if they would have scored two," Cora said. "He was going to come in if they would have scored two in the ninth because of the long inning. But it didn't happen. And now tomorrow he'll start."
Price had already been told that he would start Game 5 on Thursday, but as he warmed up in the bullpen in the eighth inning, he was mentally preparing himself to get as many outs as his team needed Wednesday night.
"Close this one out tomorrow or close this one out today, start tomorrow and do something special," Price said. "This is a cool experience. Being in the bullpen for me is obviously different, but it's still baseball."
Cora's bullpen management continued to be near-perfect after Rick Porcello lasted only four innings Wednesday. Joe Kelly allowed a run during the fifth inning, but Ryan Brasier got five outs, then Matt Barnes retired the lone batter he faced, turning the lead over to Kimbrel.
Kelly's run was the first allowed by the trio this postseason, raising the group's ERA to a whopping 0.50 in 18 combined innings.
Cora knew he planned to extend Kimbrel to two innings, so the one out from Barnes was all the manager wanted. The right-hander had recorded 14 four-out saves during his career, but none of five-plus outs. He had two career postseason saves of four outs, one in 2013 and one in Game 1 of the ALDS against the Yankees earlier this month.
But six outs? That was uncharted territory for the seven-time All-Star.
Those six outs didn't come easily, but when all was said and done, Kimbrel was shaking hands with his teammates, one step closer to the World Series.
"This time of year, you leave it all out there," Kimbrel said. "I was giving everything I had. Obviously it wasn't my best, but this is the playoffs; there are 27 outs and you have to get the last one. I've made it a little bit exciting the last couple games, but I'm glad we were able to pull out the win."
Even after throwing a season-high 35 pitches -- the most he's thrown in an outing since he threw 37 against the Yankees on Aug. 9, 2016 -- Kimbrel said he will "absolutely" be available for Game 5. And if Cora asks him to throw two innings on Thursday, he'll be ready for that, too.
"Whatever I need to do," Kimbrel said. "You have a chance to go to the World Series, we'll do what we have to do."
Mark Feinsand, an executive reporter, originally joined MLB.com as a reporter in 2001.