Rookie Jayson Tatum scored 24 points - his ninth 20-point game of the postseason - and Boston beat Cleveland 96-83 on Wednesday night to take a 3-2 lead in the best-of-seven Eastern Conference finals.
The Celtics held James to two fourth-quarter points, earning their 10th straight victory in Boston to remain perfect at home this postseason and move within one win of their first trip to the NBA Finals since 2010.
''I just enjoy playing in the big moments, in the big games. That's when I have the most fun,'' said Tatum, who needs one more 20-point game to tie Kareem Abdul-Jabbar's rookie record of 10 in a postseason.
''I can't say it enough: We're one win away from being in the finals,'' Tatum said. ''The playoffs bring the best out of people.''
Game 6 is in Cleveland on Friday night, with the decisive seventh game back in Boston on Sunday if necessary. The home team has won every game so far in the series, and none has been closer than nine points.
''We're looking forward to having an opportunity to force a Game 7,'' said James, who had 26 points and 10 rebounds but also had six turnovers. ''It's up to us to see if we can come back here for one more.''
Al Horford had 15 points and 12 rebounds, and 21-year-old Jaylen Brown had 17 points for Boston. Tatum added seven rebounds, four assists and four steals one day after finishing a single vote shy of a unanimous selection to the NBA's All-Rookie team.
''The sky's the limit" for Tatum , Brown said. ''He's going to continue to get better. He's my workout partner. I expect it in myself and I expect it in him.''
Kevin Love scored 14 points for the Cavaliers, who are trying to reach the finals for the fourth consecutive season. James has played to the end in seven straight seasons.
To extend that streak, he'll need to win two in a row.
One of them will be in Boston.
''Our focus - LeBron's focus - is to win,'' Cleveland coach Tyronn Lue said. ''That's the only thing that matters.''
The Celtics opened a double-digit lead in the first quarter and nursed it the rest of the way, holding on through a four-minute scoring drought that saw Cleveland score nine straight points to cut the deficit to 83-71. But Terry Rozier hit Horford with an alley-oop to snap the skid, and that was as close as the Cavs would get.
James had one basket on four shots in the fourth quarter, and afterward conceded that he was worn down. He finished 1 for 6 from 3-point range in the game; the Cavaliers made just 9 of 34 attempts from beyond the arc and shot just 42 percent overall.
''I had my moments, but I think everybody at this point is tired, worn down whatever the case may be,'' he said. ''I was still trying to make plays, put our team in position to win.''
GOONING IT UP
Boston went on a 15-3 run in the first quarter to turn a three-point deficit into a nine-point lead. The Celtics scored nine in a row at the end of the first quarter and into the second to take a 36-19 lead, their biggest of the game.
That's when the Cavaliers fought back .
After a hard defensive play by Morris sent Larry Nance Jr. into the first row of seats, Morris appeared to wander over and say something. Nance to jump up and body checked him; Morris responded with a one-handed shove to the face.
Aron Baynes and Brown came in to break it up, and Terry Rozier put a body on Nance. After a review, the referees called technicals on Rozier, Nance and Morris. Kyle Korver made the foul shot to make it 36-20 and Cleveland went on a 9-0 run to cut the deficit to eight points, 36-28.
But Morris made a long 3-pointer to stop the scoring drought, and soon hit another to cap an 8-2 run that made it a double-digit lead.
Smart said the Celtics wanted to more aggressive at home.
''At their place, they were the aggressor,'' he said. ''That showed and they came up with the victory. We just wanted to be that team tonight.''
Teams that win Game 5 to take a 3-2 lead in a best-of-seven series win 83 percent of the time. ... James had 16 points, four rebounds and three assists at the half. Tatum had 13 points, and Horford had 10 points and seven boards at the break. ... Baynes made his first start of the series, subbing for Morris. ... It took until midway through the third quarter for a Cavs starter other than James or Love to make a basket. J.R. Smith sank a floater to make it 63-50, and George Hill followed with a jumper of his own. ... The Celtics were 10-0 in the playoffs at home in 1986. ... Horford had his 7th double-double of the postseason, matching a career high he set in 2015.