Tony Parker has a game-high 21 points to lead a calm, cool Spurs squad. (Lynne Sladky/Associated Press)

They couldn’t rattle him. They couldn’t shake his team. And when Tony Parker’s high-arcing, broken-play, crazy lean-in jumper banked off the glass and in with 5.2 seconds left, already LeBron James and the Miami Heat had to cede at least one major advantage to the Spurs and their calm-amid-the-calamity point guard after Game 1 of the NBA Finals:

In the poise matchup, San Antonio’s serenity beats Miami’s chaotic, maddening desire for a second straight title — at least for the moment.

After the Spurs repelled every late Heat run, after they made sure they kept within striking distance before halftime, after they weathered nine-point deficits and a brain-lock foul of Ray Allen behind the three-point line in the final 90 seconds, there is one team playing with house money in these Finals and it’s not Miami.

Before Parker went glass for one of the more memorable Finals shots in recent memory, Duncan provided a real window into the dueling expectations of two franchises a day before Game 1.

Asked if he ever observed the scrutiny LeBron goes through — by the way, he was hammered for not being more aggressive Thursday night in a game he registered, oh, a triple double — Duncan cut the questioner off. “I’m definitely glad I don’t have that kind of pressure on me. Absolutely.”

The Post Sports Live crew previews the NBA Finals between the San Antonio Spurs and the Miami Heat. (Post Sports Live)

The Heat have to win, or else LeBron falls to 1-3 in the Finals and Pat Riley’s great free-agent coup of 2010 doesn’t accomplish its singular goal — becoming champion multiple times.

The Spurs already have established their legacy, and can take great pride in returning to the Finals after a six-year absence with the same three primary stars as 2007.

And LeBron looked like he had the world on his shoulders in the final minutes of Game 1. He grasped at the ball on the final possession with Miami trailing by 2, trying to take it away from a stumbling, bumbling Parker — before the daggar lean-in jumper banked in.

“Tony did everything wrong and everything right in the same possession,” LeBron lamented.

As the pressure mounted and the shot clock wound down, Parker somehow collected himself. And he got it to go in.

“It felt forever too,” he said. “It was a crazy play. I thought I lost the ball 3 or 4 times. I just wanted to get a shot up. And it went in.”

The final play — really, the final minutes — spotlighted the Spurs main advantage in this series: poise. They’ve got it, and that’s why they wrestled Game 1 away from the defending champions before a shaken white-clad crowd at the AmericanAirlines Arena.

 Even in his most harried moments, the Spurs guard incredibly kept his composure, finding a nook and a cranny to get free while chaos descended on him.

Bucket. Ballgame, 92-88.

One game to zero, Homegrown Big Three over Miami’s Imported Trio.

Every time the Heat threatened to go up 10 or more, the Spurs kept the game within striking distance. Every time LeBron threatened to take over the proceedings, San Antonio made a memorable defensive stop or Parker swished a jump shot through the rim that just crushed Miami’s momentum.

One of the biggest shots came with 3:30 left, putting the Spurs up 85-79 and forcing Miami to call a timeout.

LeBron tried to bring his team back, but San Antonio was so money in the clutch. Danny Green’s three-pointer with just over two minutes left and the Heat trailing by four, just siphoned emotion out of the building and made the Heat have to play perfect in the final minutes.

Yes, the Spurs did not make it easy on themselves. Green actually fouled Allen on a three-point attempt instead of getting in his grill with 1:28 left.

Those three throws cut it to 88-86. But the Spurs kept their cool, calmly working the ball around for on the next possession.

The arena shook and everyone stood when Duncan received the ball inside and drove hard to the rim.

He was met by Chris Bosh, who fouled him, and a trio of others. The 37-year-old coolly stepped to the line made both.

Parker, Duncan and Ginobili combined for 54 points, outplaying their younger and more celebrated counterparts, who combined for 48, at key stretches.

It’s not often when the game outdoes the hyperbole. But then, it’s not often when a team coming off nearly two weeks of not playing finds its rhythm and its range on the road in the NBA Finals.

Duncan was relentless after picking up two first-quarter fouls. His tip with less than six minutes left gave the Spurs an83-79 lead.

For a while, this clearly looked like Miami’s night. In fact, it was almost Wade’s game.

He scored 17 points, raining down jump shots as if it was the 2006 finals and he had found a special zone. But he went scoreless in the fourth quarter. And it wasn’t enough to disrupt San Antonio. The Spurs took Game 1 because they never got rattled.

Miami’s defense forced just four turnovers. They moved the ball like a piece of hot coal, distributing to Danny Green for four three-pointers, waiting for Ginobili to cut to the rim.

Parker was the maestro and Duncan was the hammer.

Calm and cool won over chaos.

It’s a long series, of course, and many good, veteran teams have snuck away with Game 1 of the NBA Finals only to go down to the best team in basketball eventually — see the Jazz of Stockton and Malone in 1998.

But something about the way these Spurs refused to panic felt like a bad omen for LeBron and the defending champions on Thursday in their home arena.

No team in American sports is supposed to win or else like the Heat. That pressure seemed front and center on the first night of the Finals.

For previous columns by Mike Wise, visit