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 seemed to tire in the fourth, scoring just two points on four shots. 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 per cent overall.

Tatum added seven rebounds, four assists and four steals one day after finishing one vote shy of a unanimous selection to the NBA’s All-Rookie team. Jaylen Brown scored 17, and Marcus Morris and Marcus Smart each scored 13 as reserves.

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 Jnr into the first row of seats, Morris appeared to wander over and say something. Nance jumped 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.