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 , springier, and guaranteed that the Eastern Conference playoffs would never lack for epic star power.


The rivalry still rages, at least for week or so, and beyond that no one knows. The Celtics are still riding Paul Pierce, Ray Allen and Kevin Garnett, through age and injuries and diminishing returns, against the threat of an uncertain future and the greater threat of the Heat’s sheer athleticism.


Boston struggled just to reach the Eastern Conference finals, then sputtered through the series opener, a 93-79 rout by the Heat on Monday night. LeBron James and Dwyane Wade shined from start to finish, with pretty passes, big dunks and bigger blocks.


James had a game-high 32 points and 13 rebounds. Wade had 22 points and seven assists, none better than the 80-foot pass he threw to James for a momentum-changing layup in the third quarter. That basket started a 15-6 surge by the Heat, who never let up from there, building as much as a 17-point lead in the fourth quarter.


“This is not our best basketball,” said Garnett. “I believe we have better basketball in us.”


Garnett was the only member of the Celtics’ Big 3 to play big, with 23 points and 10 rebounds. The Celtics otherwise looked slow and wobbly compared to their younger rivals. Pierce is playing with a sprained knee and Allen with a bad ankle, leaving the Celtics looking older than their age, which was already an issue, no matter how many times they deny it.


Pierce scored just 12 points — 2 after halftime — going 5 for 18 from the field. He did not attempt a free throw for just the fifth time in his long and glorious playoff career. Allen, one of the top foul shooters in the history of the game, went 3 for 7 from the line, a clear indication that his balance is off.


Allen called his injury “a battle within myself that I have to try to win,” a statement that sounded more hopeful than self-assured.


Boston’s defense held up for a time, but James and Wade eventually overpowered it, and they got just enough shooting support from Shane Battier (10 points) and Mike Miller (8 points) to keep the Celtics scrambling. Miami converted 50 percent of its field goals.


It was the repetitive image of Wade and James flying to the basket, however, that most perturbed the Celtics, a team that has long prided itself on defense. Miami scored 42 points in the paint.


“They got where they wanted to,” said Rajon Rondo, who came close to issuing a threat as he called for a tougher approach in the paint: “Nothing dirty,” he said, “but they have to hit the deck, too.”


The statement hardly fazed the Heat, whose recent series against the Indiana Pacers was filled with flagrant fouls, suspensions and general nastiness.


“That doesn’t change anything for us,” James said of Rondo’s comments. “We expect to hit the deck every single game, me and D-Wade. It’s how we feel like teams approach us. They feel like they need to put us on the floor, hard-foul us.”


Rondo was the Celtics’ most consistent weapon after Garnett, finishing with 16 points, nine rebounds and seven assists, although he also had four turnovers.


Although Miami led from wire to wire, it was a night of severe momentum swings. The Heat won the first quarter by 21-11, lost the second quarter by 35-25, and took the third quarter by 26-15. After a 6-0 burst to open the fourth, the Heat had a 78-61 lead and little concern.


Boston had just two days to recover after a stressful, seven-game series against the Philadelphia 76ers — a fact that was not lost on the Heat, who played their youth and speed to great advantage.


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


This series will be played on a strict every-other-day schedule, allowing the Celtics no time to take a breath or get healthy. Game 2 is Wednesday night.