Miami ? Just when aching exhaustion was ready to swallow him, Dwyane Wade raced the length of the court late in the game Sunday to chase a pass he had no hope of reaching, only to find his brakes didn’t work. He dove head first into the white-clad home crowd, landing five rows in, momentarily engulfed by shocked fans who weren’t sure whether to lurch out of the way or try to make a franchise-saving catch.

Wade emerged limping. It wasn’t an injury.

“Just tired,” the Heat star would say afterward. “At that moment I was spent.”

It was a snapshot to remind you why this young man is Miami’s most special and most beloved sports star ever except Dan Marino, and that gap narrows with every spectacle like this one.

Mario Chalmers had launched the long pass late in the game.

“I was mad at ‘Rio for throwing it, I’m not going to lie,” Wade said — except he was smiling.

He’d earned that smile. Earned the exhaustion, too.

Wade’s 38 points and whirling-dervish defense made sure the Heat won Game 1 of this NBA second-round playoff series vs. Boston, 99-90, with that late launch into the crowd well representing the maniacal intensity we can expect in this series.

Well, that and Sunday’s boiling emotions and flying elbows, flagrant fouls and double-technicals, scowls and angry words, the (very nearly a) head-butt and the ejection of Celtics star Paul Pierce.

Otherwise, a pretty uneventful game.

Best of all? This drama, this brutal ballet, has just begun.

Ain’t it great!?

This had to be one of the most anticipated home games in the club’s 23-year history. Surely this franchise hasn’t had a playoff series torqued up this high, full of this much animus, since Heat-Knicks in the 1997 series punctuated by an on-court brawl, suspensions and then-coach Jeff Van Gundy latched poodle-like onto the pistoning leg of Alonzo Mourning.

Sunday’s version of that lunacy included James Jones with a hard foul against Pierce, and Pierce getting in his grill and bumping his head into Jones’ face. That was just before Wade plowed hard into a screen set by Pierce, who barked profanities at Wade and found himself ejected with seven minutes left for his second technical foul.

Somebody asked Wade later what Pierce had said to him.

“Ah, a bunch of gibberish,” said Wade with a wink in his voice.

Whatever NBA “playoff intensity” means, it began to redefine itself here Sunday.

Heat-Celtics owns the marquee and the market on vitriol because this is Boston’s proud, aging past champions trying to maintain control of the Eastern Conference against Miami’s Big 3 — a team that came together to beat this very opponent.

The 10 months since LeBron James’ “Decision” have all led to this day, to this series, after an 82-game regular season and then a five-game first-round dispatch of Philadelphia cleared away all the obstacles.

The six months since Miami opened this season in Boston, losing, have been a precursor to this series.

That’s a lot of inevitability, a lot of anticipation.

Sunday, it was worth the wait.

“This is personal,” said James of this opponent.

Maybe he had that in mind when, after a hard foul by Ray Allen in the third quarter left James sprawled face down past the end-line, he theatrically did a few pushups before hopping to his feet.

The Celtics won three of four this season and had won 18 of the past 21 against Miami entering Sunday. They were the champions this Heat team was built to be.

“Our big brothers,” Wade had called them.

Could be time for a power shift.

Could be time for the little brothers to start running the family.

There are six future Hall of Famers in this series, maybe more. Sunday’s crowd included rap stars Diddy, Drake and Rick Ross. Wade was the biggest star in the house — HIS house, still, even with LeBron here now.

Remember back when so many people seemed to worry whether the superstars Wade and James could coexist?

Sunday was another example proving they could, and do.

“I know I don’t have to average 30 points,” said James. “We have other options.”

Wade, at his elbow during the postgame news conference, smiled again.

“That’s the reason why we’re playing together,” he said.

For this. For the Celtics, and beyond.