MIAMI — Five summers ago, the Boston Celtics created a new model for title contention. Two summers ago, the Miami Heat duplicated it, with parts that were newer, shinier and springier, and guaranteed that the Eastern Conference playoffs would never lack for epic star power.

The rivalry still rages, at least for another round, and beyond that no one knows. The Celtics struggled to reach the conference finals and sputtered through the series opener Monday night when the Heat took Game 1 in a 93-79 rout at American Airlines Arena.

LeBron James dominated the night from start to finish, leading the Heat with 32 points and 13 rebounds. Dwyane Wade had 22 points and seven assists, none better than the 80-foot pass he threw to James for a powerful third-quarter dunk.

“I didn’t think we played great defensively and we still held them to 93 points,” Celtics coach Doc Rivers said. “But at the pace the game was played, 93 felt like 110.”

The Celtics’ stars, who gathered in 2007, won a title and made two finals, looked slow and wobbly compared to the Heat. Although Kevin Garnett was steady (23 points, 10 rebounds), Paul Pierce struggled against the Heat’s stiff defense, finishing with 12 points and a 5-for-18 shooting line. Ray Allen had only six points, and shot 1 for 7.

Pierce was shadowed initially by James and later by Shane Battier and never did find a comfort zone. He scored two points in the second half, going 1 for 7 from the field. Rajon Rondo was the Celtics’ most consistent weapon after Garnett, finishing with 16 points, nine rebounds and seven assists, although he also had four turnovers.

The Celtics had only one day to recover after a Game 7 victory over the Philadelphia 76ers on Saturday — a fact that was not lost on the Heat.

“Our game plan was to use our energy and our effort here at home throughout the game,” Wade said.

Injuries have also taken a toll. Pierce is playing with a sprained knee, and Allen with a sore ankle, leaving the Celtics looking older than their age, which was already an issue, no matter how many times they denied it. Allen, one of the top foul shooters in the history of the game, went 3 for 7 from the line.

Three more games like this, and the Celtics will most likely be staring at the end of an era. Allen and Garnett are free agents this summer and could be let go no matter how this playoff run ends.

This game was one of severe momentum swings. Miami won the first quarter by 21-11, lost the second quarter by 35-25 and took the third quarter by 26-15. The Heat opened the fourth with a 6-0 burst for a 78-61 lead, their biggest margin to that point.

The Heat began the series without Chris Bosh, who is rehabilitating after an abdominal injury in Game 1 of the conference semifinals. Bosh worked out on the court Sunday, but his status remains “out indefinitely,” leaving the Heat to lean even more on Wade and James.

James took the first shift Monday, single-handedly outscoring the Celtics in the first quarter, 13-11, as Miami took a 10-point lead.

The Celtics were called for three early technical fouls. By the end of the night, the Celtics had earned five.

Asked if they were earned, Rivers said, “I know mine wasn’t.” He added, in a comment that could draw a fine, “Everybody has to keep their composure — not just the players and the coaches.”

Amid the surliness and frustration, Pierce found a rhythm and the Celtics found their stride, closing the half on a 13-3 run and tying the game at 46-46.

Miami and Boston have pretty much owned the East for the last seven years, making two trips each to the finals since 2006.

They are as familiar with one another as two rivals can be, with equal doses of enmity and admiration. Before the game, Heat coach Erik Spoelstra praised Rondo as “one of the most unique players I’ve seen in this league in all my years.” Rivers spoke just as glowingly of James and Wade.

“We haven’t accomplished anything,” Spoelstra said after the game. “We know that.”

There were moments in the last six months when the Celtics wondered if they would make it back to this point at all. They lost Jeff Green to a heart ailment before the season began. Pierce and Garnett fought through early injuries and spent months battling to get back in the playoff hunt.

“We’ve had a lot of stuff,” Rivers said, adding, “Paul, Kevin, Ray, Rondo — they never didn’t think they would be here. It would have been easy for them to think that, especially at the All-Star break, nothing was going right for us.”