Two nights after LeBron James saved his legacy, he extended it by winning his second NBA championship.

And in defeat, the San Antonio Spurs may have shed their "boring" moniker once and for all.

James turned in a double-double with 37 points and 12 rebounds, including the game-clinching 17-foot jumper with 27.9 second left, to lead the Miami Heat to the crown with a 95-88 victory over the San Antonio Spurs in Game 7 of the NBA Finals on Thursday night at American Airlines Arena.

The Heat now have back-to-back championships with James, who left the Cleveland Cavaliers to come to Miami with the intent of winning titles three years ago.

After falling short in the NBA Finals in 2011 against the Dallas Mavericks, the Heat's dynasty is starting to take shape.

The two exhausted continued the heavyweight championship fight they started in Game 6 when the Heat overcame a five-point deficit with 28 seconds left in regulation to win 103-100 in overtime. Neither team led by more than seven points throughout the entire game.

Dwyane Wade scored 23 points and grabbed 10 rebounds, and Shane Battier fought off a playoffs-long slump to add 18 points - on six 3-pointers -- off the bench.

"It took everything we had" to win the series, Wade said in a postgame interview. "But we're a resilient team. This is why we came together (with Chris Bosh and James for the 2010-11 season)."

Miami led 90-85 after a timeout when Wade scored a layup off an inbounds play with 2:56 left, but the Spurs answered with Kawhi Leonard's 3-pointer with two minutes left to cut the Heat lead to 90-88.

The game stayed that way until James gave his team some breathing room 92 seconds later. San Antonio's Manu Ginobili turned the ball over on the ensuing possession to give the Heat control of the game.

Tim Duncan led the Spurs with 24 points and 12 rebounds. Leonard added 19 points and 16 rebounds. Manu Ginobili added 18 points but had the costly turnover in the closing moments that cost the Spurs a chance at their fifth world title.

It was a sluggish start for both teams who showed lingering effects from Tuesday night's Game 6 drama. The Heat led just 18-16 after the first quarter.

The intensity picked up in the second quarter and remained throughout the game.