Miami led throughout - comfortably for the most part - until the very end of the third quarter. And then the Thunder rampaged through the final quarter.
But in a series billed as much as LeBron vs Durant as it is Heat vs Thunder, it was noticeable which of the two produced the key performance in the final 12 minutes. Kevin Durant scored 17 of his 36 points to lead Oklahoma City to a 1-0 lead in the best-of-seven series. James scored seven points in the fourth quarter.
Durant and Russell Westbrook outscored the Heat 41-40 in the second half by themselves. Westbrook had 27 points, 11 assists and eight rebounds.
James admitted later: "They didn't make many mistakes in the fourth quarter."
James finished with 30 points, his most in any of his 11 finals games, but had only one basket over the first 8:15 of the fourth, when the Thunder seized control of a game they had trailed for all but the final few seconds of the first three quarters.
For James, it was a painful reminder of last year's finals when he averaged just three points in the fourth quarters of the Heat's six-game loss to the Dallas Mavericks, taking almost all the blame for Miami's failure.
Dwyane Wade had 19 points but shot just 7 of 19 for the Heat, while Shane Battier scored 17 points, his highest this postseason.
Oklahoma City are now 9-0 at home in the postseason and have homecourt advantage in the finals. Miami are going to have to win at least one game in OKC to claim the championship.
"We just came out with a lot more intensity on the defensive end. Made them feel us a little bit," Westbrook said of the second half, when the Thunder outscored the Heat 58-40.
It was a different story in the first half. "Those guys they came out on fire. They were passing the ball well, knocking down shots," Durant said. "We just wanted to keep playing. It's a long game."
Thunder were prone to turnovers in the first half and were behind by as many as 13 points. It was James' supporting cast that stepped up bigger to start, the Heat hitting five of their six 3-point attempts in jumping to a 29-22 lead after one quarter.
Game 2 is on Thursday in Oklahoma City.
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image: © Keith Allison