NBA Finals: Miami Heat burn Spurs in overtime

The Miami Heat forced an already absorbing NBA Finals to a deciding Game Seven after a thrilling 103-100 overtime victory over the San Antonio Spurs on Tuesday tied the series at 3-3.

Miami trailed by 13 points in the third quarter but LeBron James, ditching his trademark headband, turned on the afterburners to spark a Heat fightback.

San Antonio were not about to roll over under the weight of the onslaught, however, rallying to eke out a five-point lead with 28.2 seconds remaining as the championship ribbons were being prepared for them courtside.

James cut the deficit with a vital three-pointer and San Antonio's Kawhi Leonard could only sink one of his two free throws to give Miami a glimmer of hope as they trailed by just three points in the closing seconds.

Ray Allen then took centre stage, finding the basket with his first successful three-point attempt of the night with five seconds remaining to send the game into overtime.

"It's going to be a shot that I remember for a long time. This will go high up in the ranks because of that situation," Allen told reporters.

Then, with the Heat trailing 100-97 in overtime, Allen and James were again decisive, sinking jump shots before San Antonio's Manu Ginobili turned the ball over while driving towards the basket.

Former Boston Celtics Allen guard then completed a memorable performance by keeping his cool to drain two free throws to give Miami a three-point lead they would not relinquish.

"It was by far the best game I've ever been a part of," said four-time MVP James.

"I'm blessed to be a part of this."

The contest had been nip-and-tuck throughout the first two quarters with 37-year-old Tim Duncan showing the consistency and accuracy that has helped carry the Spurs to four titles since 1999 as he shot 11-of-13 from the floor to tally 25 points by halftime.

The Spurs ended the half with a crowd-silencing run to lead by six at the interval with Duncan outscoring the entire Miami Big Three of James, Dwyane Wade and Chris Bosh, who had combined for just 21 first-half points.

The game started to drift away from Miami in the third and the Spurs ended the quarter with a 10-point lead as they closed in on a potential fifth NBA title.

With their season and some might say legacy on the line, Miami battled back in the fourth, with a brilliant block from James on Duncan, which the MVP immediately followed up with a basket to bring the game level at 82-82.

But James was so nearly the villain with two costly turnovers in the final stages of the fourth quarter, allowing the Spurs to get back in front as some fans began to leave the arena, convinced Miami's season was over.

Those fans were soon rushing back to their seats though ,as James and Allen forced overtime and Miami kept alive their hope of winning back-to-back titles.

"It was a hell of a game... a hell of game," San Antonio coach Gregg Popovich said.

"It was an overtime game. It's a game of mistakes and they ended up on the winning side."

Game Seven will be played in Miami on Thursday and a drained Heat coach Erik Spoelstra was clearly thrilled at the prospect of a title showdown.

"If you said when we started our (pre-season) trip to China if we could decide this season with a Game Seven in our building, every single one of us take it.

"They are the best two words in team sports -- Game Seven."