Both teams were putting on a clinic in shooting from beyond the arc and the 40 combined threes set a new NBA record.
Karl-Anthony Towns and Jimmy Butler shot 30 and 35 respectively while Jeff Teague recorded a double-double with 15 assists and 14 points.
But it still wasn’t enough to stop James, who played 48 minutes and finished with his ninth triple-double of the season.
After rising to block Butler’s go-ahead attempt second earlier, Jeff Green lobbed a half-court in-bound pass to James who connected with a turnaround jumper from the free throw line as time expired in overtime to send the fans inside Quicken Loans Arena wild.
The 140-138 win comes just one night after the Cavaliers blew a 21-point lead in yesterday’s loss to the Orlando Magic.
And James was delighted to give the Cavaliers supporters something to cheer about after their recent poor form.
“I knew he [Butler] was going to Iso once we made the switch on our rookie,” James said.
“I just tried to keep my weak side awareness and I was able to get the block and keep it in bounds, which allowed us to get that play.
“Coach Lue called up a great play, Jeff Green gave me a heck of a pass and I just trusted my instincts and let it go.
He added: “It was a great win for us, we needed this after the tough loss in Orlando last night.
“Our fans were unbelievable, our guys stuck with it even though they were shooting the heck out of the ball.
“They shot 58 per cent from the field and we were still able to get the win.
“We played Cavaliers basketball tonight and that’s all we could have asked.”