BOSTON -- Before the Cleveland Cavaliers put their perfect 15-0 start to the season to the test Tuesday night at TD Garden against the defending NBA champion Celtics, Cavaliers coach Kenny Atkinson was asked what he hoped to get out of the game.

"We want feedback," Atkinson said. "More feedback. Hopefully we'll see this team down the road and down the road in an important game. On the other hand, I don't want to blow this game out of proportion. It's that balance, but it's more anxious to see where we are. And we all know our schedule has not been the hardest.

"We're playing an elite team -- the top team in the league. So I just can't wait to get some feedback from the game."

Over the next 48 minutes, Atkinson got his wish. The result? Boston, despite a stellar push from Cleveland after halftime, had enough to hold off the Cavaliers 120-117, ending Cleveland's unblemished start.

The loss left the Cavaliers tied for the second-longest winning streak to begin a season in NBA history -- though undoubtedly earning Cleveland some respect in the process.

Respect, however, doesn't always translate to wins. And after spending almost a month with a zero in the loss column, Cleveland now has a number there thanks to a 33-point, 12-rebound, 7-assist effort from Jayson Tatum, one of six Celtics to score in double figures.

Boston went white-hot from beyond the 3-point arc, going 22-for-41 from deep, as the Celtics -- who led by as many as 21 -- held off a charge from Cleveland in the second half as the Cavaliers pounded away in the paint.

If these teams meet again in the playoffs next spring -- as they did in the Eastern Conference semifinals last season -- the matchup probably will be one split along the same battle lines as Tuesday with the Celtics trying to dominate the 3-point line and the Cavaliers attempting to do the same in the paint.

In this one, both teams got what they wanted. Boston shot 14-for-22 from deep in the first half -- the single-best 3-point shooting half by the Celtics in the past 25 years, with a minimum of 20 attempts. The Celtics, however, shot 22-for-45 from inside the arc, whereas Cleveland was 36-for-64 from 2, including owning a 60-36 edge in points in the paint.

It was a parade of trips to the rim by Cleveland in the third quarter, in particular, that allowed Atkinson's team to get back in the game, as the Cavaliers scored 22 points in the paint in the quarter alone -- as many as Boston had in the game to that point.

By then, the celebratory mood at TD Garden early gave way to a bitterly competitive one -- complete with the crowd roaring in applause and dismay in ways that would've felt at home if this had been a continuation of last spring's playoff series. That included the physicality with which both teams played, and the lack of fouls called in spite of it.

Ultimately, though, Boston had enough to hold off Cleveland's comeback, with a key Payton Pritchard 3-pointer with 5:31 remaining putting Boston up 107-100, creating enough separation to ensure Cleveland's perfect start came to a close.

For his part, Celtics coach Joe Mazzulla said he was looking at this game as an opportunity for his Celtics (12-3) to shore up specific things that have troubled them lately -- individual defense and positioning, and rebounding, in general.

How did that work out? Boston won the rebounding battle 42-41, despite playing against the combination of Evan Mobley (22 points, 11 rebounds, 6 assists) and Jarrett Allen (10 points, 11 rebounds) throughout, and with Kristaps Porzingis still recovering from offseason surgery.

Boston's individual defense, meanwhile, had a huge impact on Darius Garland, who had only eight points on 3-for-21 shooting.