Jayson Tatum scored 24 points to lead five Boston players in double figures as the Celtics took a 3-2 lead in the best-of-seven Eastern Conference finals.
Four-time NBA Most Valuable Player LeBron James led Cleveland with 26 points, 10 rebounds and five assists.
But James looked at times as if he were feeling the effects of the heavy load he has carried for the Cavs in these playoffs, coughing up six of Cleveland’s 15 turnovers, including four in the second half.
Kevin Love, with 14 points, was the only other player to score in double figures for the Cavs, who host game six on Friday trying to stay on track for a fourth straight trip to the Finals.
James himself is seeking an eighth straight trip to the title series.
The winner of the series will play either the Golden State Warriors or Houston Rockets for the NBA crown. The Western Conference rivals are locked at 2-2 in their series.
With James on the bench to open the fourth quarter, the Celtics pushed a 16-point lead to 21.
A 9-0 Cavs run reduced the deficit to 12 points, but Cleveland came up empty on their next four attempts and the Celtics pulled away again.
“Everybody just loaded to the ball,” Tatum said of the Celtics’ defensive effort. “We understand that LeBron is going to hit tough shots, make plays, but we’ve all got to help each other out.”
The Celtics improved to 10-0 at home this post-season, and Tatum said there’s no reason they can’t wrap up the series on Friday, even though so far the home team has won every game in the series.
“We’ve got to be focused, composed and play with a lot of poise and we’ll be fine,” he said, clearly up for the challenge.
“It’s my first year. We’re one win away from going to the Finals. It doesn’t get any better than that,” he said.
The Cavs got off to a rocky start, with five first-quarter turnovers nearly matching their seven field goals. James scored eight first-quarter points and Love led the way with 10 — the rest of the Cavs’ players contributing just one.
James drove past Jaylen Brown for a layup with 4:14 remaining, drawing a foul and making the free-throw to pull the Cavs within 19-15.
– Shoving match –
But Boston responded immediately with a three-pointer from Marcus Smart and closed the quarter on a 16-4 run to lead 32-19.
Frustration may have played a role as tempers flared early in the second quarter.
With 10:47 left in the period and the Celtics up 17 points, Boston forward Marcus Morris and Cleveland’s Larry Nance tangled, with Nance sent sprawling to the floor.
Morris appeared to say something to Nance before turning away, and the Cavs player rose from the floor and shoved him from behind.
As officials and other players intervened Celtics guard Terry Rozier raced into the fray and pushed Nance.
It all ended with Morris, Nance and Rozier receiving technical fouls.
Kyle Korver made the technical free throw for the Cavs along with a quick 3-pointer and an energized Cleveland team twice whittled the deficit to eight points before the Celtics reasserted themselves to lead 53-42 at half-time.