BOSTON (AP) — Armed with a raucous crowd and seemingly all the momentum after digging their way out of a 3-0 Eastern Conference finals hole, the Celtics entered their Game 7 matchup with the Heat eyeing a chance to make NBA history.

It may have evaporated on the very first play.

Jayson Tatum rolled his left ankle on a layup attempt on Boston's opening possession of the game, and he and the Celtics never were the same afterward, stumbling to a 103-84 loss on Monday night.

"I came down on my ankle. And it's tough because it kind of impacted me the rest of the night," said Tatum, who finished 5 of 13 from the field with 14 points. "Swelled up. It was frustrating that I was a shell of myself, couldn't move."

Boston was looking to extend a wild postseason ride that already included five wins when facing elimination — twice in the East semifinals after falling behind 3-2 to the 76ers, and three straight times against the Heat.

Instead, for the second straight year the Celtics' season ended with a team receiving a trophy on their home floor.

Jaylen Brown led Boston with 19 points but struggled to find a groove while going just 8 for 23 from the field and 1 for 9 from the 3-point line.

"Just a terrible game when my team needed me most," Brown said. "JT hurt his ankle the first play of the game. You could see it swelling up. He couldn't move out there. ... I failed. It's tough. I give credit to Miami. But just a terrible job."

The Celtics cut what had been a 17-point third-quarter deficit to 10 entering the fourth. But Miami started the final period with a 7-0 spurt over the first 70 seconds from with Boston never recovered.

Boston's 84 points in the night was a low for these playoffs.

Along with Tatum's injury, Malcolm Brogdon also played through what he confirmed afterward was a partially torn tendon his right forearm. And Game 6 savior Derrick White kept his team in contention with 18 points, but left late after suffering a knee injury.

"This is how the game is. Sometimes the ball doesn't roll your way," Brogdon said.

Boston ended their postseason run 5-6 at home.

"I thought in the first quarter and a half or so we continued to fight defensively, even though our shots weren't falling," coach Joe Mazzulla said. "Then we just couldn't score."

It was a microcosm of a season that began with a coaching change the day before training camp after Ime Udoka was given a yearlong suspension for having an inappropriate relationship with a woman in the organization.

Mazzulla took over and led Boston to a 57-win regular season and its fifth conference finals appearance in seven seasons.

Now Boston enters an offseason that could change the franchise's immediate future with a decision to be made about Brown, who is eligible to receive a five-year contract extension worth as much as $295 million.

But Brown said it's not something he'd even began to ponder as he comes to grips with the end of a playoff run he thought would last much longer.

"I expected to win today and move on. That's what my focus was on. That's what my focus has been on. We failed. I failed. That's all I can think about at this moment. We'll cross that bridge when we get there."