The Heat star wasn't stopped by San Antonio.
Instead, he was stopped by the San Antonio heat.
On a night where air conditioning failed and the AT&T Center turned into a steamy mess, James missed the final four minutes because of cramps and the San Antonio Spurs took full advantage.
The Spurs closed the game on a 16-3 run as the four-time NBA MVP could only watch helplessly, beating the two-time defending champion Heat 110-95 on Thursday night in a rather bizarre opener to the title series.
''After I came out of the game, they kind of took off,'' James said. ''And it was frustrating sitting out and not being able to help our team.''
The heat, not the Heat and not even the Spurs, was the story.
A power outage was blamed for the lack of cooling inside the arena, and ABC sideline reporter Doris Burke said during the network's coverage that the temperature near the court in the third quarter was 88 degrees.
Thousands of fans shed the black souvenir T-shirts that were left on their seats before the game, understandable since no one needed to wear layers on this night.
Game 2 isn't until Sunday. The NBA expects the arena's issues to be repaired by then, and neither team was scheduled to practice there Friday or Saturday anyway.
''I'm sure that both teams are going to be happy that we have a couple of days before the next game,'' Spurs coach Gregg Popovich said. ''And hopefully, we can pay our bills.''
Popovich's deadpan comedy probably got as much notice as the effort by his team, which topped Miami in Game 1 of the finals for the second straight year.
Tim Duncan scored 21 points on 9 for 10 shooting - the best percentage of his 230-game postseason career - for the Spurs, who got 19 points from Tony Parker and 16 from Manu Ginobili.
Parker felt right at home, meaning his literal home.
''Felt like I was playing in the European Championship,'' Parker said. ''We never have AC in Europe, so it didn't bother me at all.''
James led the Heat with 25 points, the last of those coming on a layup with 4:09 left that got the Heat - who led by seven with 9:38 left - within 94-92.
After that play, James couldn't move. He stood on the baseline as play went the other way, literally unable to coax another step out of his left leg.
His night was over.
Soon, so was Miami's chances.
''I think it felt like a punch in the gut when you see your leader limping like that back to the bench,'' Heat coach Erik Spoelstra said. ''But at the same time we still had an opportunity.''
Not without James, they didn't.
Not with the way the Spurs were shooting, either. San Antonio closed on a 26-7 run in the final 6 minutes. Neither heat nor Heat would slow them down on this night.
''Not NBA Finals-worthy,'' Heat guard Dwyane Wade said, speaking of the conditions, in the locker room afterward. ''I'll tell you that. This is crazy.''
Wade put an ice bag atop his head after his shower, sweat dripping off him to the point where it seemed as if he hadn't even used a towel.
Chris Bosh slumped back in his chair while drinking his fourth Gatorade of the postgame, still complaining that he couldn't move.
And while all that was happening, James was secluded in the Heat training room, getting 2-1/2 bags of intravenous fluids just so he could limp out of the arena.
Cramps have been an issue for him before, even in the NBA Finals. When temperatures started soaring Thursday night, he knew he was in trouble.
''It was an unusual circumstance,'' James said. ''I never played in a building like that.''
He drank as many liquids as he could at halftime, changed into a dry uniform, put cold packs on his neck during stints on the sideline. In the end, nothing was enough.
It's not the first time electricity has had a significant impact on a championship event in recent years.
The Super Bowl in 2013 between Baltimore and San Francisco was marred by a power outage at the Superdome in New Orleans, interrupting play for 34 minutes.
''It's frustration and there's anger,'' James said. ''But at the same time, it's something you try to prevent, you try to control. I got all the fluids I needed to get. I did my normal routine I've done. It's something that was inevitable for me tonight.''