The Boston Celtics fought off a spirited challenge from short-handed Cleveland Monday, beating the Cavaliers 109-102 to take a commanding 3-1 lead in their NBA Eastern Conference semi-final series as Oklahoma City leveled their series with Dallas in a wild finish, Azernews reports citing to Fox sports.

Jayson Tatum scored 33 points and grabbed 11 rebounds and Jaylen Brown added 27 points for the Celtics, who will try to finish off the best-of-seven series at home on Thursday (AEST).

The Cavaliers were dealt a heavy blow when Donovan Mitchell, who had averaged more than 35 points over the six prior games, was ruled out with a calf injury, joining starting centre Jarrett Allen on the sidelines.

NBA superstar LeBron James, who led the Cavs to their only NBA title back in 2016, was sitting courtside with his agent Rich Paul, but with Mitchell absent the Cavs ultimately didn’t have enough firepower.

James’ attendance was somewhat notable given he can opt out his contract with the Los Angeles Lakers and become a free agent in the summer.

The superstar was initially drafted by the Cavs and spent seven seasons there before a move to Miami in 2010.

But James returned in 2014 and led Cleveland to its first NBA championship in 2016.

The Cavs kept the pressure on, taking the lead briefly on Darius Garland’s driving basket early in the third quarter — their first lead since the first quarter.

But the Celtics quickly reasserted themselves and led by 10 going into the final period.

Cleveland, on the back of 30 points from Garland, pulled within five points three times in the final four minutes, but Brown, fed by Tatum, connected on a three-pointer with 1:09 to play that effectively sealed it.

“It’s a game of runs,” Tatum said after the Celtics struggled to put the depleted Cavaliers away.

“It’s not going to be perfect every single time. They’re going to make shots, but it’s our job to figure it out.”

The Celtics, winners of a league-best 64 regular-season games, used a 12-0 scoring run to take charge in the first quarter, Tatum scoring 16 points in the period.

Boston led by as many as 13 in the second quarter but Tatum cooled off and Cleveland, buoyed by 11 of their 15 three-pointers in the first half, battled back, twice cutting the deficit to one point before going into the break down by five.