Mitchell Robinson (right) and the Knicks smothered Jaylen Brown and the Celtics early Friday night in Game 6, holding them to 37 points in the first half.
Mitchell Robinson (right) and the Knicks smothered Jaylen Brown and the Celtics early Friday night in Game 6, holding them to 37 points in the first half.Danielle Parhizkaran/Globe Staff
NEW YORK — Last June, the final night of the Celtics’ season ended with coach Joe Mazzulla drenched in beer and champagne and already thinking about how to win another NBA championship.
On Friday, the last night of the Celtics’ season ended with Mazzulla walking slowly and quietly down a long concrete ramp in the bowels of Madison Square Garden, where a bus would take him past long-starved Knicks revelers whose night of celebration was just beginning.
The Celtics came here for Game 6 of this Eastern Conference semifinal with hope and momentum, and a belief that despite the 3-2 series deficit, despite Jayson Tatum’s left foot being in a cast, they still had a fighting chance. They did not think their dreams would vanish, at least not yet.
Then the game started, and it turned into an avalanche. Knicks 119, Celtics 81, a game just as lopsided as it appears.
The Knicks won the series, 4-2, and advanced to the conference finals for the first time in 25 years. The Celtics, meanwhile, failed to become the first team to repeat as champions since the Warriors in 2018.
The Celtics’ locker room emptied quickly afterward. No music played, no television was on, and, most tellingly, no limbs were wrapped in ice, because there was no longer another looming game to consider.
“Losing to the Knicks feels like death,” forward Jaylen Brown said. “But I was always taught that there’s life after death, so we’ll get ready for whatever’s next in the journey. I’ll be ready for it.”
After last season’s title, Celtics president of basketball operations Brad Stevens brought back the entire core, in large part, he said, because he felt that group deserved the chance to chase greatness together again.
This group came up short, and now the Celtics will confront a summer that could be rife with change. The team is projected to have a salary and luxury tax bill that exceeds $500 million, which would be the most any franchise has ever paid to run a basketball team.
That truth, combined with restrictive measures that come from operating above the second salary apron, could have led the front office to pursue cost-cutting measures.
Then the path became even more uncertain Monday, when Tatum ruptured his Achilles’ tendon on this same court in the final minutes of Boston’s Game 4 loss.
One month ago, there were visions of a new Celtics dynasty. Now, the future is pocked with uncertainty. After Friday’s loss, the Celtics were in no mood to consider what might come next. They were still thinking about what had just eluded them.
“It sucks,” guard Derrick White said. “You’ll never get this season back. You’re never going to have the exact same team again.”
Knicks fans crammed into Madison Square Garden on Friday in search of something to celebrate and eager to set aside their tortured history. Really, they could not even dream of the level of success the Celtics have achieved this century.
Over the last 18 seasons, the Celtics have been to nine conference finals and four NBA Finals, and won two championships. The Knicks had not reached a conference final since 2000, and their fans were pros at heartache.
Derrick White leaves the court after the Celtics' loss to the Knicks Friday night in Game 6. The team faces an uncertain future with Jayson Tatum's injury and salary cap problems.
Derrick White leaves the court after the Celtics' loss to the Knicks Friday night in Game 6. The team faces an uncertain future with Jayson Tatum's injury and salary cap problems.Danielle Parhizkaran/Globe Staff
Set against that backdrop, it would probably not have taken long for the Celtics to puncture this raucous environment and cause decades of anxiety to seep out.
But that did not happen. The Knicks took a 6-5 lead just over four minutes into the game and never trailed again. New York led by as many as 27 points in the second quarter and 41 in the third.
The dismantling was so thorough that it is impossible to focus on one area in which the Celtics were compromised. You could close your eyes and throw a dart and be sure to hit one.
New York held massive advantages in second-chance points (25-11), points in the paint (48-34), and in transition (23-8). It was such a bludgeoning that Mazzulla started going deep into his bench during the third quarter, a normally unfathomable move in an elimination game, but a logical one in this extreme case.
“Extremely tough night for us,” center Kristaps Porzingis said. “It felt like nothing was going our way, and just the game was easy for them.”
The loss ended a confounding and frustrating postseason for Porzingis, who continued to battle extreme fatigue related to a mysterious March illness that was never identified. As he sat at a locker after the loss, he said that if he laid down there, he would fall asleep instantly.
He played just 11 minutes Friday, and throughout this series the Knicks pulverized the Celtics whenever the talented big man was on the floor.
“I tried to give what I had,” Porzingis said. “It wasn’t much, as you could see.”
Porzingis said he might eventually undergo further medical testing, but for now he is hopeful that a lengthy stretch of rest will help him get back to feeling normal.
Porzingis has one year remaining on his two-year, $60 million contract, and the Celtics could seek trades for him. The same could be true for point guard Jrue Holiday, who turns 35 next month and will earn $32.5 million next season. Al Horford, who turns 39 next month, could consider retirement.
Regardless, Tatum’s recovery will be the storyline of the season. He remained in New York after his surgery and met with the Celtics at their team hotel Thursday night. The players said the discussions had nothing to do with basketball.
“Mostly, it’s tough,” said White, Tatum’s closest friend on the team. “A guy that loves basketball as much as he does, and it’s probably the worst injury he’s ever had, so just try to encourage him. He’s starting a long journey and he’s going to do everything he can to get back out there and play.”
The expectations have already been reset, but it remains to be seen whether this is all just a roadblock for a team still capable of sustained greatness, or an end.
In the locker room after Friday’s loss, Mazzulla told his players that coaching them this season was one of the greatest honors of his life. But he acknowledged that in this profession, there is bound to be much more heartbreak than joy.
“So when you step into the arena and you go after something,” he said, “that’s how it goes.”
Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.