The Rockets lead the Western Conference finals 3-2.
James poured in 46 points with 11 rebounds and nine assists.
George Hill enjoyed his best game of the series for the Cavaliers with 20 points, while reserve Jeff Green chipped in 14 and Larry Nance Jr. hit for 10 points.
His performance was a sight to behold.
Celtics head coach Brad Stevens could only chuckle when asked if it ever comes into his mind that his team is facing a generational talent like James.
James now has 13 career playoff games with at least 40 points, 10 rebounds, and five assists, the most such games in National Basketball Association postseason history.
Griezmann shone, Atlético Madrid win Europa League
The France forward was quoted by Marca as saying after the game: "Now is not the time to talk about the future". Griezmann, who has been with Atletico since 2014, is on a contract that runs to 2022.
It was his seventh 40-point game in this year's playoffs.
Kevin Love was not diagnosed with a concussion nor placed in the league's protocol in the first few hours after his nasty collision with Jayson Tatum, but all of that could still change. He spent the rest of the contest in the locker room while being evaluated for a concussion.
Things turned for good in the second quarter, when the Celtics could only manage 18 points. He finished with 46 points, 11 rebounds and nine assists, that included two unbelievable dagger 3-pointers in the final minutes. Overall, the Cavs shot 47.1 percent from the field, including 39.1 percent from beyond the arc. "It's just all about just win every game and it should put us in position to play for a championship".
The Celtics' All-Star forward Al Horford was also unusually quiet with just six points while guard Terry Rozier had 28 and Jaylen Brown 27 points.
He was especially aggressive in the first half, when he piled up 25 points to help Cleveland build a double-digit lead.
There were about four minutes left to play when Brown missed the 3-pointer, but Boston could not get any closer the rest of the way. But, most importantly, Boston was manhandled on the glass.