CLEVELAND — Payton Pritchard has been waiting all season for a night like this, when the threes were splashing, his deceptive strength would lead to swished fadeaways, and he would carry the Celtics when they desperately needed a lift.
Without Derrick White and Neemias Queta, who both got the night off, the Celtics were spearheaded by the smallest man on the floor Sunday at Rocket Arena. Pritchard (42 points) helped Boston stave off multiple rallies and sank two free throws with 5.9 seconds left as the Celtics escaped Cleveland with a 117-115 win.
The Cavaliers looked cooked, but rallied by scoring 11 points in the final 72 seconds, including two long 3-pointers from Donovan Mitchell and another triple from Darius Garland with 1.2 seconds left to cut the Celtics lead to 116-115.
Jaylen Brown was fouled and split to free throws, giving the Cavaliers a chance at a victory. But Boston rookie Amari Williams defended Evan Mobley well and forced an airball.
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Pritchard led all scorers on 15-for-22 shooting, while Brown collected his fourth career triple-double (19 points, 12 rebounds, and 11 assists), despite an off shooting night.
Jordan Walsh helped with 14 points and 11 rebounds, including a key bucket with 2:24 left.
The shorthanded Celtics had no answer for Mobley, who scored the first 8 points of the third quarter and Jaylon Tyson, who added a 3-pointer to slice Boston’s lead to 65-62. But Pritchard sparked a game-changing run with some contested jumpers and finally a 3-pointer as the Celtics raced to an 86-65 lead.
Boos rained down from Rocket Arena as the Cavaliers lacked energy and were slopping. But Mobley kept plugging with a pair of dunks and a 3-pointer as the Cavaliers sliced 10 points off that lead by quarter’s end.
Pritchard had 27 points entering the fourth while Mobley had 25 points and 10 rebounds.
In the first half, Brown was erratic from the field and Pritchard was in foul trouble, so coach Joe Mazzulla used Anfernee Simons to keep the Celtics offense respectable.
Simons responded with 16 first-half points, including a pull-up 3-pointer with 1.9 seconds left to complete a 9-0 quarter-ending run and a 58-51 halftime lead.
Xavier Tillman actually stole the inbounds pass after the Simons bucket and flipped in a prayer but officials ruled he released it after the buzzer. Still, the Celtics built a lead despite 11 first-half turnovers and 2-for-9 shooting from Brown.
Pritchard finished with 18 points in less than 12 minutes on 7-for-8 shooting. With the Celtics shorthanded at center, Mobley had his way in the paint with 10 points and six rebounds while Garland added 8 points.
The Cavaliers’ Donovan Mitchell shoots over Xavier Tillman during the second quarter Sunday.Jason Miller/Getty
Mitchell was rather quiet in the first two periods with 5 points, but that included a resounding two-handed dunk on Simons.
Pritchard was on his way to a standout game, knocking down his first three shots, two of those 3-pointers as the Celtics raced to a 13-2 lead. His lone obstacle from a season-best night was foul trouble.
Pritchard picked up his first foul 19 seconds into the game and got his second halfway through the first quarter, making contact with Garland on a 3-point attempt, forcing Mazzulla to pull him despite 10 points.
The Cavaliers lead the NBA in 3-point attempts per game and chased down the Celtics with the 3-ball. Four of their first five field goals were 3-pointers, as the Celtics helped the Cleveland rally with a series of turnovers, including an offensive foul and fumbled pass from Brown.
A night after pouring in 41 points against Minnesota, Brown scored 5 points in the opening quarter as the Celtics clung to a 28-26 lead. Their six turnovers led to 8 Cleveland points.
Gary Washburn is a Globe columnist. He can be reached at gary.washburn@globe.com. Follow him @GwashburnGlobe.
