Love did not return with concussion-like symptoms, and his status for Sunday's Game 7 is unknown.
For the eighth straight year, James' team will represent the Eastern Conference in the NBA Finals. James has already passed Chicago Bulls great Michael Jordan as the all-time leading playoff scorer, and the "greatest of all time" debate is raging once again.
With the Cavs' backs against the wall, James pushed the issue all night to fight out of the corner, attacking Celtics defenders big and small with an array of moves off the bounce, in the half-court and in transition.
But the game ultimately came down to the C's going through one of its scoring lulls, getting behind by double digits and not making that one shot or getting that clutch defensive stop to swing the momentum in their favor.
"Greatness", Cavs coach Tyronn Lue said. "If you want to win, that's what it takes". "Right around the trade deadline, no matter if we made a trade or not at that point in time, I kind of just switched my mindset on saying, 'Let's get this most out of this season I can.' I'm determined to get the most".
Boston won its three games at home and the Cavs proved to be unbeatable in Cleveland. James is now averaging 33.9 points per game in 22 career shots at elimination.
"I kept faith in them and they did that". You've got to be able to handle a punch or two. "You're not going to get anywhere by looking ahead or behind. you have to stay in the moment".
"I'll be available for at least four more games", James said, "and we'll see what happens".
For James, a potential free agent, the victory postponed a decision about his future until next month.
Then his team went out and proved it.
"I'm very fortunate and blessed to have (James) on our side this time", quipped George Hill after the win.
James didn't know until after the game that teammate Larry Nance Jr. had banged into him. Multiple games now in TD Garden, held them under 100, three games in the 80s - but he still scored 35.
After a bright start by the Celtics, who took the first quarter 25-20, the Cavaliers led from midway through the second quarter.
How about Jeff Green with 14 points.
After Kevin Love went down halfway through the opening quarter, the signs looked ominous for the Cavaliers but it wasn't to be this time.
George Hill has been a different player in opposing venues throughout the first six games of the East Finals - and he enjoyed the home cooking on Friday night, finishing with 20 points on an efficient 7-for-12 shooting from the floor and ideal 6-of-6 from the line, adding three boards, three assists and a pair of steals.