BOSTON — Consider it a rivalry renewed.

A rested and refreshed Sixers team lost, 117-101, to a diminished group of Celtics in Game 1 of the Eastern Conference Semifinals.

It was a Celtics team withered by injury to its three most dynamic players: Kyrie Irving, Gordon Hayward and, in their Game 7 first-round win over the Bucks two days before, Jaylen Brown. It was a Celtics team that should have been exhausted after it needed the entire allotted number of games to dispatch the Giannis "The Greek Freak" Antetokounmpo.

It also was a Celtics team led by a brilliant young coach, Brad Stevens, who is 41, and a brilliant young player, rookie Jayson Tatum, who is barely 20.

They played a Sixers team led by rookie-of-the-year favorite Ben Simmons at point guard and second-year center Joel Embiid, who already is an all star. All signs point to a decade of East Coast corridor animosity.

"When you look at the whole league, and you look at the future of the league, we're up there. They're up there," Embiid said. "It's going to be fun the next couple of years."

Tatum, who scored 28 points, seemed particularly intent on shaming the Sixers. They traded a future first-round pick to move up two spots and take guard Markelle Fultz No. 1 overall in the 2017 NBA draft. Fultz missed 68 games to a mysterious shoulder injury and did not play Monday night.

Celtics fans chanted "He's-a-rookie!", mocking Simmons' ROY candidacy compared to Tatum's. Simmons was injured last season and did not play, which some consider an unfair advantage. Simmons heard it.

"I'm OK," said Simmons, who finished with seven turnovers. Also, 18 points, seven rebounds and six assists … but, seven turnovers. "It didn't affect me at all."

There's more. After the draft, Celtics general manager Danny Ainge claimed Tatum was his top choice all along.  As if Philadelphians needed more reason to despise Danny Ainge.

Ainge acted as provocateur and shooting guard for some of the most memorable Sixers/Celtics clashes. He was a kid when John "Havlicek stole the ball!" and broke the hearts of Sixers fans in Game 7 of the 1965 Eastern Conference finals, and he was fresh off his Brigham Young University career when the Sixers blew their three-games-to-one lead in the 1981 conference finals. Ainge was part of the near re-run in 1982, but the Sixers won Game 7 in Boston, whose fans implored them to "Beat LA!" (they did not). And he was on the 1984 squad that brawled with the Sixers during a regular-season game in the old Boston Garden after Larry Bird started a fight with Julius Erving.

Sixers coach Brett Brown showed his team video of what tooth-and-nail basketball looked like before they were born. Roughhouse center Joel Embiid's favorite clip was no surprise:

"Dr. J and Larry Bird, holding each other's necks."

Holding. Quaint.

There might have been a bit of rust on the Sixers' wheels. They dispatched the Heat in five games and hadn't played in six days.

"We were very rusty," Simmons said. "We got smacked multiple times, and we didn't react."

Which, of course, is unacceptable, said Embiid:

"We're NBA players. We're in the playoffs. We've got to be ready every game. We weren't ready tonight."

Maybe they weren't ready, but there's a real chance they weren't able, either. Not yet, anyway.

If nothing else, Game 1 offered a glimpse into what should be a terrific fortnight of basketball. Both teams presented matchup mismatches for the other, but the Celtics are a more proficient defensive team and, so, were less compromised. At least, they were less compromised Monday. The Sixers had no answer for Tatum, or quicksilver point guard Terry Rozier, who hit seven of nine three-pointers — the Celtics made 17 of 36 (the Sixers missed 21 of their 26 threes) — or all-star big man Al Horford, who finished with 26 points.

Embiid, of course, poses a problem for everyone. He finished with 31 points and 13 rebounds. The mask he has worn for the last four games to protect his healing orbital bone seemed not to bother him at all.

The city that chanted "Beat LA!" as the Sixers finished them in Game 7 of the 1982 Eastern Conference finals gave away T-shirts that said "Beat PhiLA," unimaginative word play that served at least one purpose:

It reminded everyone of bygone animosity between two elite basketball teams.

Which is wonderful.