Who would doubt them now? Another wild ride on the Celtics roller coaster ends with a Boston victory and a trip home for Game 7

Winner goes to the NBA Finals; loser goes home. Who would doubt the Celtics now?

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As a delirious section of Celtics fans waited out the stunned departures of their Miami counterparts inside the Kaseya Center, as they happily remained in their seats chanting “Let’s Go Celtics” while the home fans rued the loss, the clock ticked toward 11:30 p.m. The celebration went on, just as this amazing Celtic season goes on, too, reviving itself only moments after it seemed dead for good.

In a fourth quarter that almost defies explanation — or description — the Celtics watched in shock as the 10-point lead they held with 4:56 to go in the game disappeared in a flash, the redux of their Game 2 meltdown at home seemingly repeating itself with another late-game nightmare. Suddenly, there stood Miami star Jimmy Butler with the game in his hands, at the free throw line with three seconds left, a replay proving he’d been fouled by Al Horford behind the 3-point line. Out to prove the promise he’d made after a Game 5 loss in Boston that his Heat would close out the series at home, he swished the three shots, sending the building into pure delirium, a 102-101 Heat lead that seemingly won them the series.

Celtics coach Joe Mazzulla called time out (of course he did in this upside down, crazy night), and when he sent White to the opposite sideline with the ball, and White would inbound the ball to Marcus Smart, Smart let loose with a three-pointer that circled in and out of rim. Game over? The home team and the home fans sure thought so, their cheers cascading from the rafters to the court.

Not so fast.

Because there was the speeding White, having sprinted to the basket after delivering the ball, tipping it in just as time expired, knowing the moment he’d done it that he’d won the game, running toward his bench signaling basket. When replay officials agreed, he was swamped by his teammates, absorbed in their hugs, and awash in their gratitude.

What an ending. What a game. What a night. What a series. From 0-3 down to a win at home away from a return trip to the NBA Finals.

“Don’t measure a man when everything is going well, measure a team or a group or an individual when adversity hits,” Jaylen Brown said. “And it hit us like a storm. Can’t get worse than the playoffs being down that much and look at how we responded? We were down three games and nobody has ever been able to come back from that. But four or five teams have been able to force a Game 7. That tells you the group we have is special. Sometimes you need a little bit of luck to bring it home.

“Tonight it was an amazing game and an incredible play at the end.”

And now… “Game 7,” Brown said, “the best two words in sports.”

Now, the Celtics have to go win the whole thing. Not just Game 7, which of course would be historic, making them the first NBA team in 150 tries to erase a 3-0 playoff deficit. But even if they do pull that off, and it sure is tough to think an already gassed Miami team can rebound from losing this game this way, it only resonates forever if the Celtics cap it with a title. Otherwise, it’s just a case of wasted drama, a footnote to what might have been.

But again, who would doubt them now? “Those guys had a choice to make and they chose to believe in each other,” Mazzulla said. “At the end of games like that, our guys talk about just crashing at the end of the game, get another chance and White made a great play.”

They got back on the court, and played, literally, to the final buzzer.

“That moment shows everything we are,” Brown said. “That moment we could have chose to throw in the towel. That’s what everyone was thinking. But no, that’s not how we want to go out. … We’re not all the way there. We got to come out and win game 7.”

Remember after Game 3, what Smart said? “Don’t let us get one.”

Remember after Game 5, what Brown said? “They let us get two; don’t let us get another one.”

There’s only one left, and the Celtics have to get it. Seems like the only fitting finale from these cardiac, comeback Celtics.

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Celtics Notebook: Malcolm Brogdon sidelined for Game 6

Tara Sullivan is a Globe columnist. She can be reached at tara.sullivan@globe.com. Follow her on Twitter @Globe_Tara.