Jayson Tatum tossed in a game-high 33 points and Jaylen Brown finished with 27 as the visiting Boston Celtics beat the undermanned Cleveland Cavaliers 109-102 in Game 4 of the NBA Eastern Conference semifinals.

The victory on Monday gives the Celtics a 3-1 edge in the best-of-seven series. The teams will play Game 5 on Wednesday in Boston.

“I thought both teams played really hard,” Boston coach Joe Mazzulla said.

“I just thought you have to make plays down the stretch. So they made a tonne of plays and put a tonne of pressure on us, and we made a tonne of plays. I thought both teams brought it.

“Everybody talks about clutch offence, I thought our clutch defence was good. We got stops when we needed to. … We executed our late-game defence. That’s just as important as the offence.”

Donovan Mitchell, Cleveland’s leading scorer, did not play because of a leg injury. Mitchell, who averaged 31.7 points per game in the first three contests of the series, strained his left calf in the final minutes of Boston’s 106-93 victory in Game 3 on Saturday.

The Cavaliers fell to 12-16 in games Mitchell has missed this season.

Fourth-seeded Cleveland received 30 points and seven assists from Darius Garland plus 19 points apiece from Evan Mobley and Caris LeVert. Mobley also had a team-high nine rebounds.

“[Garland] knows he’s capable,” Cavaliers coach JB Bickerstaff said. “We’ve seen Darius carry this team before, so it’s not a surprise. He just knew what he had to do in order to give us a chance tonight, and I thought he did it.”

“They gave us everything that they had,” Bickerstaff said of his opponents.

“They competed at a high level. They played the game properly. I’m proud of the guys, the way they went out and scrapped and competed and gave ourselves a chance.”

King James watches on

LeBron James sat courtside and watched the Cavaliers beat Celtics, an appearance certain to drive conversation about the superstar’s future.

James, who can opt out of his contact with the Los Angeles Lakers and become a free agent this summer, arrived just as Game 4 began. He took a seat across from Boston’s bench next to his wife, Savannah, and agent Rich Paul.

During a timeout in the first quarter, James received a thunderous ovation when shown on the giant scoreboard during sitting in an arena he made famous.

His postseason over for weeks, James was back home in Ohio. He acknowledged the roaring crowd and then King James mimicked placing a crown on his head.

Oklahoma City Thunder level series with Dallas Mavericks

Meanwhile, Shai Gilgeous-Alexander scored 34 points and the Oklahoma City Thunder overcame a Dallas franchise playoff-record 13 blocks, rallying for a 100-96 victory to even their Western Conference semifinal series at 2-2.

Chet Holmgren and Lu Dort hit clutch 3-pointers late, and Jalen Williams drove for a dunk and a 94-91 lead with 1:29 remaining as Dallas players and coaches screamed for a double-dribble call.

The teams split a pair on each other’s home court. Game 5 is Wednesday night in Oklahoma City.

PJ Washington led Dallas in scoring again with 21 points, while Doncic had 18 points, 12 rebounds and 10 assists. Kyrie Irving had his second single-digit scoring game of the series with nine points.