LOS ANGELES (AFP) — Jayson Tatum scored 33 points as the Boston Celtics ended the Cleveland Cavaliers’ 15-game unbeaten start to the season with a hard-fought 120-117 victory in the National Basketball Association (NBA) Cup on Tuesday.

The Celtics unleashed a barrage of 22 three-pointers to overwhelm Cleveland, who clawed their way back to within two points of the lead late in the game after trailing by 21 early in the second half.

Despite the Cleveland fightback, reigning NBA champions Boston held their nerve and kept the scoreboard ticking over to close out a deserved win.

Tatum’s 33 points included six three-pointers while the Boston star added 12 rebounds and seven assists in an all-round Celtics effort that saw six players finish in double figures.

Tatum said Boston’s championship pedigree had helped the Celtics over the line as Cleveland threatened late in the game.

“We’ve played a lot of basketball, we’ve played in the biggest games,” Tatum said.

“NBA is a bunch of talented teams — guys are gonna make plays, they’re gonna make shots.”

“I say it all the time — how you respond shows your growth and how special your team is.”

Tatum admitted that ending Cleveland’s unbeaten record, which has left them sitting on top of the Eastern Conference, had motivated the Celtics.

“They came in 15-0 feeling like they were the best team. We felt like we were the best team — it’s all competition. We were ready to play today,” Tatum said.

Cavaliers coach Kenny Atkinson said his team had been caught off-guard by Boston’s superior intensity.

“They had playoff force and physicality, we had regular-season force and physicality,” Atkinson said.