After losing two of their top three scorers, the Celtics failed to regain their first place in the Eastern Conference on Sunday, falling to the Cleveland Cavaliers 115-111.

Boston blew a 12-point lead in the fourth quarter while starters Jaylen Brown and Derrick White were sidelined with illness and injury, respectively.

In the absence of Brown and White, Mazzulla fielded a revamped lineup, with Sam Hauser starting for the first time of the season and Kristaps Porzingis and Al Horford starting together for the first time since April. Surprisingly, Mazzulla also added Drew Peterson to his rotation, giving the reserves significant minutes, including in crunch time.

Hauser and Peterson both set season highs for minutes played, and backup Payton Pritchard played most games outside of overtime. Pritchard scored 24 points, Jayson Tatum finished with 33 and eight rebounds and Porzingis had his most productive outing of the season (21 points on 7 of 17 shooting, eight rebounds, three steals).

But the Celtics couldn’t overcome Donovan Mitchell’s 35 points and Cleveland’s 17-for-36 performance from 3-point range. The Cavaliers matched Boston’s total number of three-pointers made with 13 fewer attempts.

The loss ended the NBA-best seven-game winning streak for Boston, which entered Sunday in first place in the East, half a game behind Cleveland. The two meetings between the conference leaders this season were decided by a total of seven points.

The Celtics looked flat in the opening minutes, missing their first five shots as Cleveland took an early 8-0 lead. Porzingis finally broke the ice with a 3-pointer, after which the Celtics found a more consistent rhythm.

Porzingis scored nine points in the first quarter and was Boston’s most efficient offensive option early on. His rim protection was also helpful against a Cavs team that put up a team-high 60 points in the teams’ first meeting.

A three-pointer from Pritchard eight minutes later gave the Celtics their first lead of the night. Cleveland led 28-24 after one quarter.

As the second quarter began, Mazzulla reached the bottom of his depth chart and inserted Peterson, a second-year winger from USC who has played most of his significant professional basketball in the G League.

Peterson, one of Boston’s three two-way players, entered Sunday with just 30 career NBA minutes played, most of which ended in losses. But Mazzulla kept the slender 25-year-old on the floor for almost the entire second quarter, only removing him for the final 0.3 seconds. He was a plus-2 in the frame when Boston entered the game and then erased a double-digit deficit.

With 6.1 seconds left in the second, Peterson drew a foul after a missed shot by Tatum and made both free throws, sending the Celtics into halftime trailing 51-49. Peterson played another 13 minutes in the second half and finished the game with eight points on 2 of 6 shooting (2 of 5 from three), four rebounds and one steal.

Boston dominated the third quarter and outscored Cleveland 35-21. Tatum accounted for 17 of those points with his perfect 6-for-6 shooting, and Hauser made the difference on both ends with two three-pointers and two steals. Luke Kornet, a healthy DNP in Friday’s win over Chicago, blocked three Cavaliers shots after checking in late in the quarter, including a flying dunk attempt from Donovan Mitchell.

The Celtics center celebrated the rejection with Dikembe Mutombo’s signature finger wag.

But just like their visit to TD Garden last month, the Cavs bounced back. Trailing by 12 with eight minutes to play, they went on a 9-0 run and then tied the score at 101-101 with 1:37 left when Mitchell broke away from Jrue Holiday’s perimeter defense and fired a three-pointer.

Tatum failed to convert contested layups on the Celtics’ next two possessions, and Cleveland got quick shots from Mitchell and Evan Mobley to go up 105-101. Two free throws from Porzingis made it a two-point game with 26.2 seconds left, and two more from Mitchell extended the lead back to four.

Pritchard, who played the entire fourth quarter for the second straight game, scored eight points in the final 17.2 seconds, twice cutting Cleveland’s lead to one. But that was the best Boston could do. Pritchard intentionally missed his final free throw and collected his own rebound, but illegally entered the lane before the ball touched the rim, resulting in a turnover.

Cleveland scored 43 points in the fourth quarter.

The loss began Boston’s busiest week of the season – a five-game sprint in seven days, including back-to-back games. The Celtics host Miami on Monday, Detroit on Wednesday, Milwaukee on Friday and Memphis on Saturday.

Porzingis and Horford both typically don’t play on consecutive nights, so Mazzulla may have to get creative with his lineups again when the Heat visit Causeway Street, especially if Brown and/or White are unavailable.

White watched Sunday’s game from the bench in Boston. He wore a David Pastrnak Bruins jersey and no visible boot or brace on his sprained right ankle.

Originally published: December 1, 2024 at 8:40 pm EST