Coach J. B. Bickerstaff lauded Evan Mobley's "will to win" after the rookie "stepped up big" in the Cleveland Cavaliers' stunning comeback victory against the Boston Celtics.

The Cavaliers moved to 9-5 with their sixth win in seven games on Saturday, making this their best start to a season since 2016-17 – a year in which LeBron James led the team to the third of four straight NBA Finals visits.

This latest 91-89 triumph was particularly impressive as Cleveland trailed by 19 points when Mobley returned to the game late in the third quarter.

"We keep talking about chemistry and bonding and belief in one another, and that was on full display tonight," said Bickerstaff. "That's the only way you can explain it.

"There's no basketball reason we should have won that game, but there was a collective spirit that refused to allow us to lose that game. That's what we keep talking about brewing in that locker room.

"Don't get me wrong, some guys made critical plays and carried their weight, but it's the spirit of that basketball team, that has that fight in them, that won't give up."

Several of those critical plays belonged to third overall pick Mobley, who finished with 19 points, nine rebounds, three blocks and two steals in 40 minutes. Of those, 12 points, two blocks and a steal came in the fourth quarter as he played its entirety.

No player in the NBA scored more clutch points than Mobley's six on Saturday, albeit tied with the Celtics' Jayson Tatum – who the Cavs man was asked to stop.

"It's the will to win basketball games," Bickerstaff said of Mobley's best trait. "Literally the only thing that matters to him is: how do I help this team win?

"Not only was it the block, but it's the free throws, it's the baseline jumper, it's the post move to get to the finish. It was an array of different things.

"Then at the end of the game, we had him on Jayson Tatum. We put him on the other team's best player. Whatever it takes to win, he's willing to do it.

"He's not satisfied with these small victories or these small moments. He understands what he wants long-term, and he understands that in order to get there, you've got to do it every night.

"He didn't start out blazing, he was working his way through it in the first half. Then as the game got going, he found his way. And when it was clutch time, he stepped up big."

Mobley has quickly proven a threat from anywhere on the court in his short time in the NBA but is especially effective at the rim, making 70.1 per cent of his attempts.

In fact, 36.8 per cent of his successful field goal attempts have been dunks, with his 32 made dunks ranking joint-third in the NBA. Team-mate Jarrett Allen's 47 lead the way, while no team can rival the Cavaliers' combined 98.

Allen's latest dunk put Cleveland up with 35.9 seconds left against Boston, and Darius Garland said: "It's super fun, just bringing all the crowd into it, the arena gets pumped up. I like seeing it a lot."

Bickerstaff, whose team rank fourth in the league for points in the paint (672), added: "We want to put pressure on the rim, and however we can do that, we'll take it.

"Jarrett is an elite lob threat, and when you put that much pressure on the rim, defenses get concerned. Even if it's only two points, it's an emphatic two points, and defenses don't like that. Then they start to collapse and we've got wide open threes.

"We've got guys who we feel like can dominate the paint – that's our objective: offensively, we want to dominate the paint as much as we can."