Champion Celtics circle NBA Cup showdown with undefeated Cavaliers

Cleveland visits the Celtics on Tuesday with defending champion Boston shooting to become the first team to defeat the Cavaliers this season.

The second NBA Cup game for each team is a rematch of the playoff series dominated by the Celtics last season, when Cavs All-Star Donovan Mitchell was relegated to cheerleader due to injury.

“It’s great for the NBA, right?” Cleveland coach Kenny Atkinson said. “Everybody is going to be watching, and I know our guys are anxious. I know they remember last year. We’re going well. They’re going well. It’s great for the league. Great for our franchise. We’re excited.”

The Cavaliers became the fourth team to start an NBA season with 15 straight victories when they beat Charlotte 128-114 on Sunday.

The Golden State Warriors (2015-16), Houston Rockets (1993-94) and Washington Capitols (1948-49) are the only NBA teams who’ve matched that start (15-0).

Only the 2015-16 Warriors extended their winning streak to 16 games. Golden State went 24-0 in 2015-16 before losing its first game.

“I just think they have a very similar group, and I think just having another year of chemistry and continuity together under your belt is important,” Boston forward Sam Hauser said. “And for them, it’s looked really good to this point. But we’re excited to try to put a loss in their loss column.”

Cleveland prevailed Sunday playing without Mitchell (rest). The All-Star signed a massive contract in the offseason and leads the team in scoring at 24.6 points per game.

Mitchell didn’t play because of a left calf strain in the final two games of last year’s Eastern Conference semifinals, when the Celtics eliminated the Cavaliers in five games.

Isaac Okoro and Dean Wade both sustained ankle injuries during the second half of Sunday’s win.

Cleveland is averaging a league-high 123.7 points per game. Boston allowed a season-high 76 points in the paint during a 126-123 overtime victory against Toronto on Saturday.

“I feel like overall just giving up too many layups,” Boston’s Jaylen Brown said after the Toronto victory. “I feel like our defense could be better. I feel like there were way too (many) easy shots in paint and that’s kind of been the theme, so we got to figure that out.”

“Individual defense and rebounding,” added Boston coach Joe Mazzulla. “Those are the biggest areas we’ve gotta get better at. We’ve just gotta guard the ball and we’ve gotta rebound as a team.”

Cleveland beat Chicago 144-126 in its first NBA Cup game on Friday. Boston’s opened NBA Cup play with a 117-116 loss to Atlanta on Nov. 12.

“It’s going to be a great test for us,” Atkinson said. “They obviously play a different style, five-out with five shooters, so it’s going to be a real good test for us. We’re at that point right now — 15-0 and let’s test ourselves against the best and see where we stand and see where we’re going to make adjustments or not make adjustments.”

Boston’s Jrue Holiday sat out Saturday’s victory over Toronto with a knee injury, but Mazzulla said he expects Holiday to play against Cleveland. Saturday marked the first time Holiday has not played in a game this season.

“Obviously, they’re a really good team,” Boston point guard Payton Pritchard said. “They’ve got a lot of good guards, good length. I feel like their bigs are playing well. Obviously, their guards (Mitchell and Darius Garland) are All-Star-level guards.

“So it’s going to be a good matchup. We’re looking forward to it. It’s going to be competitive and, hopefully, the Boston crowd comes out.”