Donovan Mitchell scored 35 points and the Cleveland Cavaliers avenged a heartbreaking loss with a 115-111 victory over Boston on Sunday in a matchup of the NBA's top teams.

Mitchell scored 20 points in the fourth quarter as the Cavs rallied from 14 points down in the second half to defeat the reigning NBA champions.

The Cavaliers started the season 15-0 but suffered their first loss at Boston last month by 120-117 and dropped their two prior games, both losses to Atlanta, before staging a fightback home triumph.

"For us, we've got to go out there and make a statement," Mitchell said.

"They beat us in the NBA Cup. No excuse. We've got to go out there and try to build – we had two losses that really hurt," he went on to say. "We weren't playing like ourselves – we needed this win."

The Cavs improved to 18-3 to stay atop the Eastern Conference while the Celtics fell to 16-4 as Cleveland snapped their seven-game win streak.

"You've got to trust your work and what we've been working on since training camp. That's the biggest thing," Mitchell said. "That's what you saw tonight, and that's what it's going to continue to be."

The Celtics were without starting guards Jaylen Brown due to illness and Derrick White with a sprained right foot.

"Just because they've got two guys down, they've got a lot of guys who are capable," Mitchell said. "You've got to respect them – they're champions for a reason."

Cleveland led 51-49 at half-time but the Celtics dominated the third quarter for an 84-72 lead entering the fourth, Jayson Tatum scoring 17 of his 33 points in the third period to lead Boston.

Mitchell responded for Cleveland, including a floater that gave the Cavs a 103-101 lead with 67 seconds remaining and concluded his run of 11 consecutive Cavaliers points.

"The biggest thing is you've just got to pick your spots, find your moments throughout the game," said Mitchell. "They kind of went on a run and in the fourth quarter I started to make my imprint.

Tatum missed a layup and Mobley followed with a dunk for a 105-101 Cavs lead. Porzingis responded with two free throws with 26 seconds to play but Mitchell sank two free throws of his own for a 107-103 Cavs lead.

The teams traded free throws late until Pritchard deliberately missed one trying to get a rebound, but he committed a lane violation and Mitchell added two final free throws to seal the victory.

"At the end of the day, we executed on both ends of the floor," said Mitchell.

"I scored offensively but we were getting stops and finding ways to get rebounds, loose balls, different things," he added. "That's what ultimately ended up getting us the W." (AFP)