LeBron James didn’t offer any hints during the regular season that these playoffs would be defined by his late-game poise, that he would be able to silence detractors of his supposedly suspect shooting — especially in the clutch — by making ridiculous jumpers to end series and careers.

This role as a closer is fresh, like a newly unwrapped present — and it couldn’t have come at a better time for the Miami Heat.

After a miserable week of weak late-game shortcomings that contributed to a five-game losing streak, James stood before his teammates in the locker room in early March and told them, “I’m not going to continue to fail late in games.”

At the time, the declaration could’ve been interpreted as hubris masking humiliation, the words of a fallen hero hoping to convince himself, and those within earshot, that he remained calm and steady even when everything around him appeared to be crumbling.

But nearly three months later, James has proved to be prophetic and has figured out how to finish games — either through monstrous dunks and unconscionable jumpers or confidence-crushing defense.

He also has figured out how to share those duties with Dwyane Wade, and is now three wins from claiming his first NBA championship.

After closing the door on the Dallas Mavericks in Game 1 of the NBA Finals by guarding Jason Terry and Dirk Nowitzki and forcing Tyson Chandler to get out of his way of a rim-punishing dunk, James confidently asked a question on Wednesday that felt far from rhetorical. “Am I going to make every shot or close every game out from now on? I hope so,” James said, as the Heat carries a 1-0 lead into Game 2 on Thursday. “I don’t know.”

James’s final two baskets came when the outcome had already been settled, but he had set the stage earlier by draining three three-pointers in the third quarter, including a spinning three-pointer just in front of the Mavericks’ bench. He has repeatedly shown this postseason that he won’t shrink in tight situations, beginning with scoring 11 of the final 13 points in regulation in Game 4 of the Eastern Conference semifinals against Boston.

He appeared to turn the corner for good two nights later, when his eyes expanded and he took deep breaths while scoring the final 10 points as Miami closed out Boston, effectively ending the career of his one-time teammate, Shaquille O’Neal. James saved his best work for the Eastern Conference finals against Chicago, when he carried Miami to a victory in Game 2 by scoring nine of the Heat’s final 12 points and teamed with Wade for an incredible run to overcome a 12-point deficit in the final three minutes. He also took on the responsibility of silencing NBA most valuable player Derrick Rose.

“It comes through failure throughout the season,” James said. “Having games where we felt like we could or should have won games late and we just didn’t execute. Once we figured out how we were going to do it for the better of the team, we started to close games out. . . . I do have confidence that if I have the ball in my hands or if I get the ball in my hands, that I can make a play, not only for myself but for my teammates to help us win the game.”

Back when the Heat was faltering, when he and Wade were uncomfortable and insecure about how it all would come together, James decided to hold himself more accountable. He no longer had the crutch of claiming that he didn’t have a worthy supporting cast. He formed his own dream team with Wade and Chris Bosh and his fellow all-stars were looking, waiting for James to come through.

“I think it’s more than anything, I see him, he’s more comfortable at the end of the games,” Wade said. “He wants it. He wants to win games. He wants to be in that winning circle. So he’s going to do whatever it takes.

“Normally, I was the guy here in Miami that, at the end of games, I always had the ball in my hand. So it took time to get comfortable with that and get comfortable with saying, ‘All right, LeBron, you take it.’ And that’s part of wanting to win and wanting to do whatever it takes to win. That’s another part of putting pride and ego aside, figuring out what’s best for the team.”

His skeptics questioned whether James had the proper wiring to go with his prodigious physical gifts; that some glitch in his mental makeup prevented him from delivering in the clutch. But those theories are slowly being put to rest, mostly because James has legitimate help, which he lacked in his previous journey to the finals. “He took a bunch of role players and they went to the Finals, but in the Finals, he had to do so much,” said ESPN analyst Bruce Bowen, who had the primary defensive assignment against James when San Antonio swept the Cleveland Cavaliers in 2007. “If you look now, he’s shooting jump shots with a patience about it that’s not rushed. There’s no pressure on him. Now, he’s able to play the game, like others have played on him, because you can’t focus completely on him, because you have D-Wade and Chris Bosh on the floor. He’s able to just be a basketball player now.”

“Just seizing the moment,” James said. “Understanding this is a great opportunity for not only myself but for our team to seize the moment and try to take full advantage.”