This time, the Heat had its lead and kept it.

The memory of last season’s collapse in the fourth quarter of Game 4 against the Mavericks served as a source of constant motivation for the Heat for an entire year. On Tuesday at AmericanAirlines Arena, LeBron James and the Heat finally exorcised those demons. The Heat defeated the Thunder 104-98 in Game 4 of the NBA Finals to take a commanding 3-1 lead in the best-of-7 series.

“We had to go through something to get to the point that we are resilient and that’s going through the heartbreaking loss in the Finals last year,” Dwyane Wade said. “Really having to go back and gut-check ourselves. But you’ve got to crawl before you walk. That’s what we did.

No team has ever lost a Finals after leading a series 3-1.

Down 17 in the first quarter, the Heat recorded its largest postseason comeback in franchise history. Miami can finish off the Thunder in Game 5 on Thursday at home.

Playing with constant pain in his legs, James offered a heroic effort in the final period. He scored six points in the fourth quarter despite severe leg cramps and finished with 26 points in the game on 10 of 20 shooting.

“We talked about it before the game that you have to play with an intensity like you have nothing left by the end of the game and he did,” Heat coach Erik Spoelstra said.

James entered the fourth quarter two rebounds shy of a triple-double and finished the game with 12 assists and nine boards. In a scary moment, he was carried off the court by team trainer Jay Sabol and reserve Juwan Howard with 5:15 left in the game. James was treated for leg cramps on the sideline and James Jones took James’ place briefly in the lineup.

“I knew I wasn’t injured,” James said. “Your muscles just basically lock up on you. I wanted to walk to the bench but my muscles wouldn’t allow me to.”

James’ misfortune gave the Thunder a brief window to try and steal a game in Miami and send the series back to Oklahoma City.

After leading by as many as seven points in the fourth quarter, the Heat watched Kevin Durant tie the game at 92-92 with a pair of free throws with 4:53 left. He then put the Thunder ahead by two points on its next possession. A nervous pall fell over the arena.

In the 2011 Finals, the Heat led by 10 points in the fourth quarter of Game 4 before giving it all back and eventually losing the series. With James out of the game with an injury, history seemed to be repeating itself.

Then James popped off the bench.

AmericanAirlines Arena, which cried in pain along with James as he was being carried off the court, cheered when he trotted to the scorer’s table to reenter the game. Chris Bosh stroked a jumper with 3:42 left to tie the game at 94-94 and, like a script from a movie, James then put the Heat ahead on Miami’s next possession with a three-pointer.

“At that point, he was just trying to will his body and make something happen,” Spoelstra said.

Said Thunder coach Scott Brooks: “LeBron made an amazing shot coming back from his injury.”

James backpedaled on defense gingerly after the three-pointer, his aching legs close to collapsing all over again.

“I just wanted to make a play with the limited mobility I had at the time,” James said.