OAKLAND, Calif. — Head cocked, jaw dropped, arms extended, LeBron James stared at J.R. Smith for a few seconds. Then came the scolding, animated and intense. What was Smith thinking? For the love of basketball intelligence and situational awareness, what was he thinking?

Near the end of his greatest night of a playoff run full of heavy lifting, James was exasperated. He was shocked. And in an overtime that could have been avoided, the Cleveland Cavaliers superstar seemed broken. A Cleveland victory — or at least a final shot at victory in regulation — had been ruined with one absent-minded blunder.

It was a game that could have recast a series expected to be lopsided. Instead, it may crush Cleveland’s underdog spirit. With 4.7 seconds remaining in an NBA Finals Game 1 that the Golden State Warriors did everything to lose, Cleveland guard George Hill stepped to the foul line. The Warriors led by one. Hill made the first free throw to tie the game. But he missed the second, and that’s when a strange game turned crazy Thursday night at Oracle Arena. Smith grabbed the offensive rebound, but rather than attempting a putback or making a quick pass to set the offense up for a final shot, he started dribbling the ball toward midcourt, moving and cutting like a running back trying to avoid contact. It seemed as if he had forgotten the score, though he denied that. He acted as if Cleveland was ahead and a win required only running out the clock. Or he underestimated how quickly 4.7 seconds expire.

It may go down as the biggest blunder in Finals history. It will go down as one of the most unfortunate gaffes in all of sports history. And in the wake of Golden State’s 124-114 escape in overtime, you must wonder whether the seemingly indomitable King James can recover from this.

Not even James can save the Cavaliers from stupid. He dropped a playoff career-high 51 points to go with eight rebounds and eight assists. Even against his 15-season body of work, even against the high standard he has set during this epic playoff run, James was magnificent. He shot over the Warriors, jumped over them, passed through them and danced around them. He made the Warriors pay for their bouts of lost focus. He punished them for toying around in another playoff game. He completed an impossible three-point play to give Cleveland a two-point lead with less than a minute remaining. Still, the Cavaliers lost.

What was Smith thinking?

“I was trying to . . . bring it out to get a shot off,” Smith told reporters afterward. “I knew we were tied. I thought we were going to call [a] timeout. If I thought we were ahead, I’d have held on to the ball and let them foul me.”

Despite the enormous challenge, the night started innocently for James and the Cavaliers. Actually, it began comically.

James, the undeniable star of a Finals that doesn’t lack for twinkling athletes, announced his arrival at Game 1 by wearing a sharp gray suit with matching shorts. He looked dapper. He looked ridiculous. He looked like the most important man, on the most important basketball stage, living under scrutiny on his terms.

From the beginning, with all eyes on him, James made more than a fashion statement. He was ready to embrace the greatest challenge of his eight consecutive Finals appearances.

“You know, LeBron defines fashion,” NBA Commissioner Adam Silver said, grinning, before the game. “If LeBron is wearing shorts, it must be in.”

And if he is attempting to lift the Cavaliers beyond their limitations against a superior team, it must still be the 2018 playoffs. He scored 12 points in the first quarter and added 12 more in the second. By halftime, he had accumulated those 24 points while missing just two of 11 shots. Kevin Durant, his primary defender, couldn’t stop him. Andre Iguodala, who has had some decent moments defending James, watched from the bench, still recovering from a knee injury. Golden State rotated defender after defender, but the Warriors had no answer for James. He didn’t just control the game with his scoring. The Warriors also couldn’t isolate him and keep him from making plays for others.

But James can’t make Smith know the score and situation. There are some tasks involved with playing the Warriors, who have won two titles in the past three years, that seem impossible. Reading the scoreboard isn’t one of them. Sure, it was a brain fart. Sure, we all have them. But it can’t happen in that situation. The Warriors know they were given a gift. They could have been forced to consider James’s greatness for the next two days and recognize that this series is tighter than imagined. They will happily accept good luck, though.

Of the fateful play, Coach Steve Kerr said: “I was disappointed that we didn’t get the rebound first, then, you know, we got lucky. He could have taken a shot, but he dribbled out. I guess he thought they were ahead. Reminded me of a play — I’m a basketball junkie, so I don’t know. Derek Harper dribbled the game out, clock out with Dallas years ago. Sometimes this stuff happens. It’s just, you know, we got lucky. We got lucky.”

Then, in overtime, they took advantage of that luck. They ran past Cleveland. James was gassed. James also seemed distraught. Over his career, he has shown a knack for rebounding from disappointment. He knows how to take a punch. He has lifted the Cavaliers from huge deficits several times in these playoffs, let alone his entire career. But this one will sting. Smith’s play was the final blow. That last minute of regulation also included a controversial replay in which officials overturned a Durant charge call and ruled that James had fouled him. Durant made both free throws to tie the game. Afterward, Cavaliers Coach Tyronn Lue said Cleveland was “robbed.”

But the blunder was the story.

“They still had enough time to get a shot off,” Durant said. “They still got a shot off with that. But I thought he was looking for LeBron because I was right there. If he had tried to put a layup up, I thought I had a good chance to contest it.

“But I’m glad we don’t even got to think about that. They did a good job tonight coming in and hitting us in the mouth.”

For as hard as the Cavaliers hit, they still lost, though. James scored 51 points and played beautifully in the clutch. And they lost. Lost the game. Lost their minds. Somehow, Smith upstaged the King.

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