Watch: Celtics can't miss in first half of showdown with unbeaten Cavs

The Celtics are leading the NBA by averaging 18.9 three-pointers per game, and they almost hit that number before halftime Tuesday night. They went 14-for-22 from behind the arc on their way to an 65-48 halftime lead over the 15-0 Cavaliers.

It was a team effort, too. Six different Celtics hit multiple triples in the half, with Jayson Tatum leading the way with a perfect 4-for-4 performance from deep on his way to 17 first-half points. That's as many three-pointers as Cleveland's entire team made in the first half. 

The Cavaliers shot 4-for-14 from deep, and when a team had made as many three-pointers as their opponent has even attempted, that's a clear sign they're going to be ahead.

Cleveland's vaunted defense couldn't handle the variety of three-point shooting Boston provided. When every player on the court was making threes, including center Al Horford, Evan Mobley and Jarrett Allen's paint protection became irrelevant for Cleveland.

And when Allen did come out to contest his outside shots, Tatum made him pay on drives.

The Cavaliers have won all their games this season. But when Boston is shooting three-pointers like this, they may be impossible to beat.