There was no stopping the Celtics in Game 2, so the Heat and their fans just called it a night

Jayson Tatum led the Celtics with 27 points in Game 2 against the Heat.Matthew J Lee/Globe staff

MIAMI — With more than 10 minutes left in Game 2 of the Eastern Conference finals, many of the Heat fans who just two nights earlier had been dancing in the aisles had seen enough.

Ten minutes is an eternity in an NBA game, enough time to wipe away deficits that should seem too large for that. But there are limits.

And as the Miami fans headed out into the sticky spring night, the Celtics supporters that once appeared to be sprinkled among the crowd became more visible and audible. There were some attempts to drown out their chants, both with boos and arena music, but eventually those turned just as futile as the Heat’s comeback try.

The Celtics wiped away an early 10-point deficit and did whatever they pleased after that, roaring to a 127-102 win that was just as thorough as that score makes it appear. This series is tied at 1, and it now goes through TD Garden.

Robert Williams III blocks a shot from Miami's P.J. Tucker during the first quarter of Game 2.Matthew J Lee/Globe staff

“We pride ourselves on being one of the tougher teams,” Celtics coach Ime Udoka said, “so we knew if we matched that we’d be in good shape tonight. Not much needed to be said.”

Even though the Celtics lost Game 1 after being throttled by 25 points in the third quarter, they had reason for encouragement. They had outscored the Heat in the other three quarters of that loss, they had played without two starters, and their issue was eminently fixable.

The Heat had not done anything surprising or perplexing during their win.

“They just came out and punked us,” Udoka said.

That was a common occurrence for these Celtics at the start of this season, but not recently. And the returns of Marcus Smart and Al Horford, two of this team’s most physical and fearsome defenders, would make it much easier to ensure that this team would not be punked again.

Thursday morning turned into a roller coaster for the Celtics. Early on, it was announced that guard Derrick White, an essential reserve, would miss the game because he had returned to Boston for the birth of his first child.

Although Smart was expected to return from a foot sprain, it was unknown if he would be limited. And Horford, who entered COVID-19 protocol on Tuesday afternoon, remained doubtful.

But that changed quickly. Soon after the team’s morning shootaround, Horford was upgraded to questionable, and then just before 3 p.m. he was cleared to play. NBA protocol had previously required two negative COVID-19 tests within a 24-hour period, but that rule was amended a few weeks ago to allow for consecutive tests on a game day.

That appeared to be what happened with Horford. When he rejoined his teammates on the bus to the arena, there was a roar.

The return of Marcus Smart and Al Horford on Thursday went a long way toward Boston's Game 2 victory.Eric Espada/Getty

With both players back, the Celtics once again resembled the team that stormed through the second half of this season looking like title contenders. Smart was particularly dominant, finishing with 24 points, 12 assists, 9 rebounds, and just 1 turnover.

“Tonight that was the main goal,” Smart said. “We can’t let them outhustle us … we just wanted to come in and be the harder-playing team tonight, and we did that.”

Jayson Tatum added 27 points for the Celtics, who made 51.2 percent of their shots overall and connected on 20 of 40 3-pointers, including a blistering start in which they made 9 of 11.

Jimmy Butler had 29 points to lead the Heat, but on the heels of his 41-point outburst in Game 1, it seemed quite muted, and Smart played a key role in that.

Much like with Giannis Antetokounmpo and the Bucks, there could soon be questions about whether Miami’s star has enough help to truly make this a series. The Celtics, especially when they are healthy, just come in waves.

The Heat actually started this game quite well. They pushed to an 18-8 lead after the Celtics were slow in rotating to a few shooters, and Udoka called a timeout. His message was simple.

“Wake up,” he said.

And that is what they did. The Celtics closed the first quarter with a crushing 27-6 run, much of it transpiring after Tatum had gone to the bench with two fouls. The Celtics’ lead never dipped into single digits again, and by the third quarter this was a romp, with Smart putting the exclamation point by sending Max Strus stumbling to the ground with a step-back dribble and draining a jumper, to the delight of Boston’s bench and the increasingly loud contingent of Celtics fans.

“For us it was always next man up,” Smart said. “But it did feel good to have that unit out there that we know when we’re out there what we can do, and it showed tonight.”