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.
Reserves Marcus Morris and Marcus Smart each scored 13.