MIAMI — The San Antonio Spurs still have that winning NBA Finals formula of good defense and a little luck on offense.

Tim Duncan overcame a slow start to finish with 20 points and 14 rebounds, Tony Parker banked in a desperation jumper on a broken play with 5.2 seconds left and the Spurs withstood LeBron James’ triple-double to beat the Miami Heat 92-88 on Thursday night in a thrilling Game 1.

Parker ended up with 21 points after referees reviewed his shot to make sure it just beat the shot clock, giving San Antonio a four-point edge in the game that was close the whole way.

“We got a little bit lucky in Game 1,” Parker said. “Sometimes that’s what it takes to win games.”

Playing for the championship for the first time since sweeping James’ Cleveland Cavaliers in 2007 for their fourth title, the Spurs improved to 5-for-5 in Game 1s, hanging around for three quarters and then blowing by the defending champions midway through the fourth.

Manu Ginobili, the third member of San Antonio’s Big Three that has combined for 99 postseason victories together, finished with 13 points, and Danny Green had 12.

“It doesn’t matter how we’re categorized — old, veterans, whatever you call us, we’re in the mix,” the 37-year-old Duncan said.

San Antonio turned up its defense in the fourth quarter, limiting Miami to seven points in the first 8 1/2 minutes in returning to the finals just the way it left — with a victory over James.

James had 18 points, 18 rebounds and 10 assists in his second straight NBA Finals triple-double, but he shot only 7 of 16 against some good defense by Kawhi Leonard, and Miami’s offense stalled in the fourth quarter.

“The Spurs are the Spurs,” James said. “They’re going to put you in positions where you feel uncomfortable offensively and defensively, and every time you make a mistake, they’re going to capitalize on it.”

Game 2 is tonight.

James became a champion on this floor last year in Game 5 against Oklahoma City, but he hasn’t forgotten his first taste of the finals.