James, a four-time NBA Most Valuable Player, matched his career playoff high as two-time defending champions Miami took a commanding three-games-to-one lead in the best-of-seven Eastern Conference second-round series.
The Heat will try to wrap up the series when they host Game 5 on Wednesday.
James's mammoth effort kept the Heat on pace with the tenacious Nets throughout, but it was team-mate Chris Bosh who hit a crucial three-pointer from the right corner with 57.3 seconds left to play that gave Miami the lead for good.
"(James's) biggest play of the game after scoring that many points was getting off the ball," Heat coach Erik Spoelstra said of the play that ended with Bosh's key trey.
Double-teamed by Nets veterans Kevin Garnett and Paul Pierce, James fired the ball to team-mate Mario Chalmers, who passed it to Bosh.
"He just showed great poise and trust to be able to make a great play, a basketball play," Spoelstra said of James, noting the superstar has been criticized plenty of times when he failed to shoulder the burden of late-game shots.
"He was fantastic tonight," Spoelstra said.
Bosh's shot broke a 94-94 tie in a tense fourth quarter, and the Heat stretched their advantage with four free-throws from Ray Allen.
James completed the scoring with one more free throw -- missing the second with 1.1 seconds left to fall short of scoring 50 points in a playoff game for the first time.
He admitted he was momentarily disappointed.
"At the same time that I'm in the moment, I understand history," James said. "To put up 50 in a playoff game would have been pretty cool."
Instead he contented himself with the victory and tying his career post-season high of 49 points, first achieved while he was with Cleveland against Orlando in the 2009 Eastern Conference finals.
James made 16 of 24 shots from the field and 14 of his 19 foul shots and pulled down six rebounds.
Brooklyn coach Jason Kidd said the Nets tried to keep James out of the paint -- where he scored 22 of his points.
"Tonight, he didn't settle," Kidd said of James's aggressive play.
Dwyane Wade added 15 points for the Heat, Bosh scored 12 and Ray Allen contributed 11 off the bench.
Joe Johnson led the Nets with 18 points, one of five Brooklyn players to score in double figures.
Pierce added 16 and Deron Williams and Shaun Livingston both scored 13 points apiece.
The winners of the series will face either the Eastern Conference top seeds Indiana or Washington in the conference finals.
Indiana lead that series three games to one and will try to finish off the Wizards when they host Game 5 on Tuesday.
source: www.abs-cbnnews.com
