The Celtics took control of the series with a Game 4 win over the Cavaliers

CLEVELAND — Jayson Tatum scored 33 points as LeBron James watched from a courtside seat, as the Boston Celtics beat the Cleveland Cavaliers 109-102 in Game 4 on Monday night to take a 3-1 lead in the Eastern Conference. Semi-final series.

Jaylen Brown added 27 points for the Celtics, who can close out Cleveland with a Game 5 win on Wednesday night in Boston.

Game 6, if necessary, will return to Rocket Mortgage FieldHouse in Cleveland on Friday.

The Cavaliers have been pushed to the brink of elimination with two of their best players in street clothes on the bench, with Donovan Mitchell (calf) and Jarrett Allen (ribs) sitting out with injuries.

It wasn’t anything new for a Cleveland team that had dealt with injuries all season, but it was a big ask for the Cavaliers to try to survive without Mitchell, the All-Star guard who carried the offensive load throughout the postseason, or Allen, their main rebounder.

The top-seeded Celtics, who tended to relax at the wrong time, didn’t show much mercy to the Cavs.

Tatum gave a strong performance for the second time in a row, adding 11 rebounds and five assists. Jrue Holiday scored 16 points for Boston.

Darius Garland scored 30 points and Evan Mobley and Caris LeVert had 19 each for the Cavaliers, who stayed in touch with the Celtics and were only 10 points behind them in fourth place.

Boston led by 15 on a jumper by Brown, but Cleveland responded with a 10-2 run as Garland and Dean Wade made 3-pointers.

The Cavaliers were still within 102-97 when Brown hit a 3-pointer with 1:08 left and Boston shut down the ball at the free throw line.

James, who played 11 seasons in two separate stints for Cleveland, returned to his former home stadium, a visit that is sure to spark speculation about where he might play next.

The NBA’s scoring leader could opt out of his contract with the Los Angeles Lakers this summer, and James has said he has not made any final decisions.

The 39-year-old sat on the other side of the Boston bench between his wife, Savannah, and agent Rich Paul. James got a standing ovation from the Cleveland crowd when he appeared on the scoreboard during a timeout in the first quarter.

Despite dealing with a left knee injury for several months, Mitchell averaged 29.6 points in his first 10 playoff games — and scored 50 in a Game 6 loss to Orlando.

He injured his calf in the final moments of Cleveland’s Game 3 loss on Saturday and was added to the injury report as questionable for Sunday. Mitchell underwent around-the-clock treatment but did not have enough time to recover. He is a day-to-day forward, according to coach J.B. Bickerstaff.

Allen missed his seventh straight game due to a painful injury suffered by the center in the opening round.

After Holiday scored seven consecutive points, the Celtics led by 13 points in the second quarter and appeared ready to escape from Cleveland.

But Cleveland came roaring back when Max Strus, who had struggled with his outside shot throughout the playoffs, hit back-to-back 3-pointers in a 13-3 run that helped the Cavaliers cut the deficit to 62-57 at halftime.

Boston center Kristaps Porzingis missed his fifth straight game, but the Celtics encouraged him because he was able to put in some work on the court.

The Associated Press contributed to this report.