BOSTON (AP) — As the Celtics’ 112-88 Game 7 rout of the 76ers began to crystallize late in the third quarter, a Boston fan toting a neon pink inflatable flamingo held up a sign that read, “See you in Miami!”

Celtics-Heat: The rematch is now officially set for the Eastern Conference finals.

Last season the Celtics had a 3-2 series lead over Miami in the NBA’s version of the final four before losing in Game 6. Boston then came within a late missed jump by Miami’s Jimmy Butler of seeing its season end in Game 7 before eventually holding on to advance to the NBA Finals.

Following a championship-round loss to Golden State, this season was themed “Unfinished Business” for this latest incarnation of the Celtics as they long to get another shot at the franchise’s 18th title.

They’re hoping to carry the momentum and lessons from Sunday’s blowout win over Philadelphia into what they expect to be another slugfest with the Heat. The teams split their four regular-season matchups.

“We had another opportunity today, as a team and for myself of just to kind of bounce back,” said Jayson Tatum, whose 51 points were the most ever in a Game 7. “I was relieved, I was happy about that, just to get another chance because our season could have been over in Game 6. Just being in another Game 7. ... I was really excited, just for the moment.”

Tatum’s heroics topped the mark set by the Warriors’ Stephen Curry in the Warriors first-round win over Sacramento just two weeks ago.

It also silenced critics who began to doubt Tatum following back-to-back games in which he had trouble locating the scoring punch that put him in the MVP conversation this season.

“When he plays a well-rounded game, our team is different,” Celtics coach Joe Mazzulla said.

Boston entered just 7-9 in its last 16 home playoff games, but outscored Philadelphia 33-10 in the third quarter. That 23-point margin was the largest in any Game 7 quarter in league history.

The Celtics, who have played in more Game 7s than any team in NBA history, improved to 27-9 in those winner-take-all contests.

League MVP Joel Embiid, who became a force for the 76ers in the second half of the season after Tatum had been among the frontrunners in the first half, had nothing but praise for Tatum and the potential for the Celtics to represent the East again in the finals.

“I think they’re probably the best team in the league,” Embiid said. “They’re so talented and they got a lot of guys who can play great basketball.”

What might have been the most impressive about getting past Philadelphia was how the Celtics adjusted to claim the final two games of the series.

First, Boston benefitted from pleas from the players and the ultimate decision by Mazzulla to insert Robert Williams III into the lineup to play alongside fellow big man Al Horford. Then, the Celtics made tactical adjustment to use Williams as a third defender on the pick-and-rolls between Embiid and James Harden, forcing tougher looks for both in Game 7 in particular.

Now the Celtics will look to formulate a game plan to stop a Miami team that has fought its way back to the conference finals thanks to some epic performances by their biggest star in Butler.

It’s a challenge Tatum said the team feels ready to embrace.

“A team that we’re extremely familiar with, third time in four years I think playing them in the playoffs,” Tatum said. “Very well-coached team. They compete with the best of them. They play hard. They defend. They make plays. And they figure out a way to win games. It’s going to be fun. It’s going to be highly competitive. And I’m looking forward to it.”