Tatum, Celtics hand Cavs 1st loss to end historic start to season

The defending champion Boston Celtics handed the Cleveland Cavaliers their first loss of the season with a 120-117 victory in NBA Cup action.

The Celtics ended the Cavs' historic hot start at 15 consecutive wins following Jayson Tatum's 33-point, 12-rebound performance and the team's 22 3-pointers.

Boston shot a remarkable 53.7% from beyond the arc, while Tatum led with a team-high six made threes.

"We were excited for today. ... The (Cavs) been the best team in the league all season, 15-0," said Tatum postgame. "They came in, and they felt like they were the best team, and we feel like we're the best team. It's all in competition, so we was ready to play today."

The Celtics opened the game by holding the Cavs to their fourth-lowest scoring quarter of the season, as Cleveland put up just 20 points and went 0-for-6 from deep in the first frame.

Cavs coach Kenny Atkinson said his team's offense was "not great" in the first half. He added that Boston played with "playoff force and physicality," while Cleveland had "regular-season force and physicality."

"It's not on the players, I think that's game plan too," said Atkinson. "It's a little bit on me, maybe not prepared enough for what they were throwing at us. We adjusted in the second half, but especially that big second quarter that was too much to overcome."

The Celtics outscored Cleveland 39-28 in that second quarter and knocked down 14 threes in the first half to take a 17-point lead into the break. Cleveland stormed back in the third quarter, outscoring the Celtics 40-28 to cut a deficit that ballooned to 21 down to five.

"I had no doubt we were going to come back. Credit to Boston, they did what they do," Cavs star Donovan Mitchell told CLNS Media. "They made a lot of tough shots, made a lot of threes, but for us just continuing to fight, continuing to be that team and we persevered. This is a great test for us, and unfortunately, we didn't get the win."

The Cavs never got closer than two points from the Celtics, and a clutch lay-up from Tatum late in the fourth sealed the game.

Mitchell poured in 22 second-half points for Cleveland to finish with 35 points in a season-high 40 minutes of action.

Darius Garland struggled mightily for the Cavs, posting eight points, seven assists, and two rebounds on 3-of-21 shooting, including 0-for-6 from deep. Injuries also kept key rotation pieces Caris LeVert, Isaac Okoro, and Dean Wade on the sidelines for the club.

The 15-1 Cavs return to action Wednesday against the New Orleans Pelicans. The 12-3 Celtics next play Friday against the Washington Wizards in another NBA Cup game.